| Message ID | D3E216785288A145B7BC975F83A2ED103FEF6E4C@szxeml556-mbx.china.huawei.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Jul 30, 2013 at 09:04:56AM +0000, Zhanghaoyu (A) wrote: > > >> >> hi all, > >> >> > >> >> I met similar problem to these, while performing live migration or > >> >> save-restore test on the kvm platform (qemu:1.4.0, host:suse11sp2, > >> >> guest:suse11sp2), running tele-communication software suite in > >> >> guest, > >> >> https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg00098.html > >> >> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/102506 > >> >> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/100592 > >> >> https://bugzilla.kernel.org/show_bug.cgi?id=58771 > >> >> > >> >> After live migration or virsh restore [savefile], one process's CPU > >> >> utilization went up by about 30%, resulted in throughput > >> >> degradation of this process. > >> >> > >> >> If EPT disabled, this problem gone. > >> >> > >> >> I suspect that kvm hypervisor has business with this problem. > >> >> Based on above suspect, I want to find the two adjacent versions of > >> >> kvm-kmod which triggers this problem or not (e.g. 2.6.39, 3.0-rc1), > >> >> and analyze the differences between this two versions, or apply the > >> >> patches between this two versions by bisection method, finally find the key patches. > >> >> > >> >> Any better ideas? > >> >> > >> >> Thanks, > >> >> Zhang Haoyu > >> > > >> >I've attempted to duplicate this on a number of machines that are as similar to yours as I am able to get my hands on, and so far have not been able to see any performance degradation. And from what I've read in the above links, huge pages do not seem to be part of the problem. > >> > > >> >So, if you are in a position to bisect the kernel changes, that would probably be the best avenue to pursue in my opinion. > >> > > >> >Bruce > >> > >> I found the first bad > >> commit([612819c3c6e67bac8fceaa7cc402f13b1b63f7e4] KVM: propagate fault r/w information to gup(), allow read-only memory) which triggers this problem by git bisecting the kvm kernel (download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git) changes. > >> > >> And, > >> git log 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 -n 1 -p > > >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log > >> git diff > >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1..612819c3c6e67bac8fceaa7cc4 > >> 02f13b1b63f7e4 > 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff > >> > >> Then, I diffed 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log and > >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff, > >> came to a conclusion that all of the differences between > >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1 and > >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 > >> are contributed by no other than 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, so this commit is the peace-breaker which directly or indirectly causes the degradation. > >> > >> Does the map_writable flag passed to mmu_set_spte() function have effect on PTE's PAT flag or increase the VMEXITs induced by that guest tried to write read-only memory? > >> > >> Thanks, > >> Zhang Haoyu > >> > > > >There should be no read-only memory maps backing guest RAM. > > > >Can you confirm map_writable = false is being passed to __direct_map? (this should not happen, for guest RAM). > >And if it is false, please capture the associated GFN. > > > I added below check and printk at the start of __direct_map() at the fist bad commit version, > --- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 > +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 > @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu > int pt_write = 0; > gfn_t pseudo_gfn; > > + if (!map_writable) > + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); > + > for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { > if (iterator.level == level) { > unsigned pte_access = ACC_ALL; > > I virsh-save the VM, and then virsh-restore it, so many GFNs were printed, you can absolutely describe it as flooding. > The flooding you see happens during migrate to file stage because of dirty page tracking. If you clear dmesg after virsh-save you should not see any flooding after virsh-restore. I just checked with latest tree, I do not. -- Gleb.
>> >> >> hi all, >> >> >> >> >> >> I met similar problem to these, while performing live migration or >> >> >> save-restore test on the kvm platform (qemu:1.4.0, host:suse11sp2, >> >> >> guest:suse11sp2), running tele-communication software suite in >> >> >> guest, >> >> >> https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg00098.html >> >> >> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/102506 >> >> >> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/100592 >> >> >> https://bugzilla.kernel.org/show_bug.cgi?id=58771 >> >> >> >> >> >> After live migration or virsh restore [savefile], one process's CPU >> >> >> utilization went up by about 30%, resulted in throughput >> >> >> degradation of this process. >> >> >> >> >> >> If EPT disabled, this problem gone. >> >> >> >> >> >> I suspect that kvm hypervisor has business with this problem. >> >> >> Based on above suspect, I want to find the two adjacent versions of >> >> >> kvm-kmod which triggers this problem or not (e.g. 2.6.39, 3.0-rc1), >> >> >> and analyze the differences between this two versions, or apply the >> >> >> patches between this two versions by bisection method, finally find the key patches. >> >> >> >> >> >> Any better ideas? >> >> >> >> >> >> Thanks, >> >> >> Zhang Haoyu >> >> > >> >> >I've attempted to duplicate this on a number of machines that are as similar to yours as I am able to get my hands on, and so far have not been able to see any performance degradation. And from what I've read in the above links, huge pages do not seem to be part of the problem. >> >> > >> >> >So, if you are in a position to bisect the kernel changes, that would probably be the best avenue to pursue in my opinion. >> >> > >> >> >Bruce >> >> >> >> I found the first bad >> >> commit([612819c3c6e67bac8fceaa7cc402f13b1b63f7e4] KVM: propagate fault r/w information to gup(), allow read-only memory) which triggers this problem by git bisecting the kvm kernel (download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git) changes. >> >> >> >> And, >> >> git log 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 -n 1 -p > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log >> >> git diff >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1..612819c3c6e67bac8fceaa7cc4 >> >> 02f13b1b63f7e4 > 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff >> >> >> >> Then, I diffed 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log and >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff, >> >> came to a conclusion that all of the differences between >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1 and >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 >> >> are contributed by no other than 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, so this commit is the peace-breaker which directly or indirectly causes the degradation. >> >> >> >> Does the map_writable flag passed to mmu_set_spte() function have effect on PTE's PAT flag or increase the VMEXITs induced by that guest tried to write read-only memory? >> >> >> >> Thanks, >> >> Zhang Haoyu >> >> >> > >> >There should be no read-only memory maps backing guest RAM. >> > >> >Can you confirm map_writable = false is being passed to __direct_map? (this should not happen, for guest RAM). >> >And if it is false, please capture the associated GFN. >> > >> I added below check and printk at the start of __direct_map() at the fist bad commit version, >> --- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 >> +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 >> @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu >> int pt_write = 0; >> gfn_t pseudo_gfn; >> >> + if (!map_writable) >> + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); >> + >> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { >> if (iterator.level == level) { >> unsigned pte_access = ACC_ALL; >> >> I virsh-save the VM, and then virsh-restore it, so many GFNs were printed, you can absolutely describe it as flooding. >> >The flooding you see happens during migrate to file stage because of dirty >page tracking. If you clear dmesg after virsh-save you should not see any >flooding after virsh-restore. I just checked with latest tree, I do not. I made a verification again. I virsh-save the VM, during the saving stage, I run 'dmesg', no GFN printed, maybe the switching from running stage to pause stage takes so short time, no guest-write happens during this switching period. After the completion of saving operation, I run 'demsg -c' to clear the buffer all the same, then I virsh-restore the VM, so many GFNs are printed by running 'dmesg', and I also run 'tail -f /var/log/messages' during the restoring stage, so many GFNs are flooded dynamically too. I'm sure that the flooding happens during the virsh-restore stage, not the migration stage. On VM's normal starting stage, only very few GFNs are printed, shown as below gfn = 16 gfn = 604 gfn = 605 gfn = 606 gfn = 607 gfn = 608 gfn = 609 but on the VM's restoring stage, so many GFNs are printed, taking some examples shown as below, 2042600 2797777 2797778 2797779 2797780 2797781 2797782 2797783 2797784 2797785 2042602 2846482 2042603 2846483 2042606 2846485 2042607 2846486 2042610 2042611 2846489 2846490 2042614 2042615 2846493 2846494 2042617 2042618 2846497 2042621 2846498 2042622 2042625 Thanks, Zhang Haoyu
On Mon, Aug 05, 2013 at 08:35:09AM +0000, Zhanghaoyu (A) wrote: > >> >> >> hi all, > >> >> >> > >> >> >> I met similar problem to these, while performing live migration or > >> >> >> save-restore test on the kvm platform (qemu:1.4.0, host:suse11sp2, > >> >> >> guest:suse11sp2), running tele-communication software suite in > >> >> >> guest, > >> >> >> https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg00098.html > >> >> >> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/102506 > >> >> >> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/100592 > >> >> >> https://bugzilla.kernel.org/show_bug.cgi?id=58771 > >> >> >> > >> >> >> After live migration or virsh restore [savefile], one process's CPU > >> >> >> utilization went up by about 30%, resulted in throughput > >> >> >> degradation of this process. > >> >> >> > >> >> >> If EPT disabled, this problem gone. > >> >> >> > >> >> >> I suspect that kvm hypervisor has business with this problem. > >> >> >> Based on above suspect, I want to find the two adjacent versions of > >> >> >> kvm-kmod which triggers this problem or not (e.g. 2.6.39, 3.0-rc1), > >> >> >> and analyze the differences between this two versions, or apply the > >> >> >> patches between this two versions by bisection method, finally find the key patches. > >> >> >> > >> >> >> Any better ideas? > >> >> >> > >> >> >> Thanks, > >> >> >> Zhang Haoyu > >> >> > > >> >> >I've attempted to duplicate this on a number of machines that are as similar to yours as I am able to get my hands on, and so far have not been able to see any performance degradation. And from what I've read in the above links, huge pages do not seem to be part of the problem. > >> >> > > >> >> >So, if you are in a position to bisect the kernel changes, that would probably be the best avenue to pursue in my opinion. > >> >> > > >> >> >Bruce > >> >> > >> >> I found the first bad > >> >> commit([612819c3c6e67bac8fceaa7cc402f13b1b63f7e4] KVM: propagate fault r/w information to gup(), allow read-only memory) which triggers this problem by git bisecting the kvm kernel (download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git) changes. > >> >> > >> >> And, > >> >> git log 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 -n 1 -p > > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log > >> >> git diff > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1..612819c3c6e67bac8fceaa7cc4 > >> >> 02f13b1b63f7e4 > 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff > >> >> > >> >> Then, I diffed 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log and > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff, > >> >> came to a conclusion that all of the differences between > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1 and > >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 > >> >> are contributed by no other than 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, so this commit is the peace-breaker which directly or indirectly causes the degradation. > >> >> > >> >> Does the map_writable flag passed to mmu_set_spte() function have effect on PTE's PAT flag or increase the VMEXITs induced by that guest tried to write read-only memory? > >> >> > >> >> Thanks, > >> >> Zhang Haoyu > >> >> > >> > > >> >There should be no read-only memory maps backing guest RAM. > >> > > >> >Can you confirm map_writable = false is being passed to __direct_map? (this should not happen, for guest RAM). > >> >And if it is false, please capture the associated GFN. > >> > > >> I added below check and printk at the start of __direct_map() at the fist bad commit version, > >> --- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 > >> +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 > >> @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu > >> int pt_write = 0; > >> gfn_t pseudo_gfn; > >> > >> + if (!map_writable) > >> + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); > >> + > >> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { > >> if (iterator.level == level) { > >> unsigned pte_access = ACC_ALL; > >> > >> I virsh-save the VM, and then virsh-restore it, so many GFNs were printed, you can absolutely describe it as flooding. > >> > >The flooding you see happens during migrate to file stage because of dirty > >page tracking. If you clear dmesg after virsh-save you should not see any > >flooding after virsh-restore. I just checked with latest tree, I do not. > > I made a verification again. > I virsh-save the VM, during the saving stage, I run 'dmesg', no GFN printed, maybe the switching from running stage to pause stage takes so short time, > no guest-write happens during this switching period. > After the completion of saving operation, I run 'demsg -c' to clear the buffer all the same, then I virsh-restore the VM, so many GFNs are printed by running 'dmesg', > and I also run 'tail -f /var/log/messages' during the restoring stage, so many GFNs are flooded dynamically too. > I'm sure that the flooding happens during the virsh-restore stage, not the migration stage. > Interesting, is this with upstream kernel? For me the situation is exactly the opposite. What is your command line? -- Gleb.
>> >> >> >> hi all, >> >> >> >> >> >> >> >> I met similar problem to these, while performing live migration or >> >> >> >> save-restore test on the kvm platform (qemu:1.4.0, host:suse11sp2, >> >> >> >> guest:suse11sp2), running tele-communication software suite in >> >> >> >> guest, >> >> >> >> https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg00098.html >> >> >> >> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/102506 >> >> >> >> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/100592 >> >> >> >> https://bugzilla.kernel.org/show_bug.cgi?id=58771 >> >> >> >> >> >> >> >> After live migration or virsh restore [savefile], one process's CPU >> >> >> >> utilization went up by about 30%, resulted in throughput >> >> >> >> degradation of this process. >> >> >> >> >> >> >> >> If EPT disabled, this problem gone. >> >> >> >> >> >> >> >> I suspect that kvm hypervisor has business with this problem. >> >> >> >> Based on above suspect, I want to find the two adjacent versions of >> >> >> >> kvm-kmod which triggers this problem or not (e.g. 2.6.39, 3.0-rc1), >> >> >> >> and analyze the differences between this two versions, or apply the >> >> >> >> patches between this two versions by bisection method, finally find the key patches. >> >> >> >> >> >> >> >> Any better ideas? >> >> >> >> >> >> >> >> Thanks, >> >> >> >> Zhang Haoyu >> >> >> > >> >> >> >I've attempted to duplicate this on a number of machines that are as similar to yours as I am able to get my hands on, and so far have not been able to see any performance degradation. And from what I've read in the above links, huge pages do not seem to be part of the problem. >> >> >> > >> >> >> >So, if you are in a position to bisect the kernel changes, that would probably be the best avenue to pursue in my opinion. >> >> >> > >> >> >> >Bruce >> >> >> >> >> >> I found the first bad >> >> >> commit([612819c3c6e67bac8fceaa7cc402f13b1b63f7e4] KVM: propagate fault r/w information to gup(), allow read-only memory) which triggers this problem by git bisecting the kvm kernel (download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git) changes. >> >> >> >> >> >> And, >> >> >> git log 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 -n 1 -p > >> >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log >> >> >> git diff >> >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1..612819c3c6e67bac8fceaa7cc4 >> >> >> 02f13b1b63f7e4 > 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff >> >> >> >> >> >> Then, I diffed 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log and >> >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff, >> >> >> came to a conclusion that all of the differences between >> >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1 and >> >> >> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 >> >> >> are contributed by no other than 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, so this commit is the peace-breaker which directly or indirectly causes the degradation. >> >> >> >> >> >> Does the map_writable flag passed to mmu_set_spte() function have effect on PTE's PAT flag or increase the VMEXITs induced by that guest tried to write read-only memory? >> >> >> >> >> >> Thanks, >> >> >> Zhang Haoyu >> >> >> >> >> > >> >> >There should be no read-only memory maps backing guest RAM. >> >> > >> >> >Can you confirm map_writable = false is being passed to __direct_map? (this should not happen, for guest RAM). >> >> >And if it is false, please capture the associated GFN. >> >> > >> >> I added below check and printk at the start of __direct_map() at the fist bad commit version, >> >> --- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 >> >> +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 >> >> @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu >> >> int pt_write = 0; >> >> gfn_t pseudo_gfn; >> >> >> >> + if (!map_writable) >> >> + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); >> >> + >> >> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { >> >> if (iterator.level == level) { >> >> unsigned pte_access = ACC_ALL; >> >> >> >> I virsh-save the VM, and then virsh-restore it, so many GFNs were printed, you can absolutely describe it as flooding. >> >> >> >The flooding you see happens during migrate to file stage because of dirty >> >page tracking. If you clear dmesg after virsh-save you should not see any >> >flooding after virsh-restore. I just checked with latest tree, I do not. >> >> I made a verification again. >> I virsh-save the VM, during the saving stage, I run 'dmesg', no GFN printed, maybe the switching from running stage to pause stage takes so short time, >> no guest-write happens during this switching period. >> After the completion of saving operation, I run 'demsg -c' to clear the buffer all the same, then I virsh-restore the VM, so many GFNs are printed by running 'dmesg', >> and I also run 'tail -f /var/log/messages' during the restoring stage, so many GFNs are flooded dynamically too. >> I'm sure that the flooding happens during the virsh-restore stage, not the migration stage. >> >Interesting, is this with upstream kernel? For me the situation is >exactly the opposite. What is your command line? > I made the verification on the first bad commit 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, not the upstream. When I build the upstream, encounter a problem that I compile and install the upstream(commit: e769ece3b129698d2b09811a6f6d304e4eaa8c29) on sles11sp2 environment via below command cp /boot/config-3.0.13-0.27-default ./.config yes "" | make oldconfig make && make modules_install && make install then, I reboot the host, and select the upstream kernel, but during the starting stage, below problem happened, Could not find /dev/disk/by-id/scsi-3600508e000000000864407c5b8f7ad01-part3 I'm trying to resolve it. The QEMU command line (/var/log/libvirt/qemu/[domain name].log), LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ QEMU_AUDIO_DRV=none /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci.0,addr=0x3,bootindex=2 -netdev tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci.0,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci.0,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci.0,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci.0,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci.0,addr=0x9 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb -watchdog-action poweroff -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa Thanks, Zhang Haoyu
Hi, Am 05.08.2013 11:09, schrieb Zhanghaoyu (A): > When I build the upstream, encounter a problem that I compile and install the upstream(commit: e769ece3b129698d2b09811a6f6d304e4eaa8c29) on sles11sp2 environment via below command > cp /boot/config-3.0.13-0.27-default ./.config > yes "" | make oldconfig > make && make modules_install && make install > then, I reboot the host, and select the upstream kernel, but during the starting stage, below problem happened, > Could not find /dev/disk/by-id/scsi-3600508e000000000864407c5b8f7ad01-part3 > > I'm trying to resolve it. Possibly you need to enable loading unsupported kernel modules? At least that's needed when testing a kmod with a SUSE kernel. Regards, Andreas
>Hi, > >Am 05.08.2013 11:09, schrieb Zhanghaoyu (A): >> When I build the upstream, encounter a problem that I compile and >> install the upstream(commit: e769ece3b129698d2b09811a6f6d304e4eaa8c29) >> on sles11sp2 environment via below command cp >> /boot/config-3.0.13-0.27-default ./.config yes "" | make oldconfig >> make && make modules_install && make install then, I reboot the host, >> and select the upstream kernel, but during the starting stage, below >> problem happened, Could not find >> /dev/disk/by-id/scsi-3600508e000000000864407c5b8f7ad01-part3 >> >> I'm trying to resolve it. > >Possibly you need to enable loading unsupported kernel modules? >At least that's needed when testing a kmod with a SUSE kernel. > I have tried to set " allow_unsupported_modules 1" in /etc/modprobe.d/unsupported-modules, but the problem still happened. I replace the whole kernel with the kvm kernel, not only the kvm modules. >Regards, >Andreas
On Mon, Aug 05, 2013 at 09:09:56AM +0000, Zhanghaoyu (A) wrote: > The QEMU command line (/var/log/libvirt/qemu/[domain name].log), > LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ QEMU_AUDIO_DRV=none /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci.0,addr=0x3,bootindex=2 -netdev tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci.0,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci.0,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci.0,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci.0,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci.0,addr=0x9 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb -watchdog-action poweroff -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa > Which QEMU version is this? Can you try with e1000 NICs instead of virtio? -- Gleb.
On Aug 5, 2013, at 4:35 PM, "Zhanghaoyu (A)" <haoyu.zhang@huawei.com> wrote: >>>>>>> hi all, >>>>>>> >>>>>>> I met similar problem to these, while performing live migration or >>>>>>> save-restore test on the kvm platform (qemu:1.4.0, host:suse11sp2, >>>>>>> guest:suse11sp2), running tele-communication software suite in >>>>>>> guest, >>>>>>> https://lists.gnu.org/archive/html/qemu-devel/2013-05/msg00098.html >>>>>>> http://comments.gmane.org/gmane.comp.emulators.kvm.devel/102506 >>>>>>> http://thread.gmane.org/gmane.comp.emulators.kvm.devel/100592 >>>>>>> https://bugzilla.kernel.org/show_bug.cgi?id=58771 >>>>>>> >>>>>>> After live migration or virsh restore [savefile], one process's CPU >>>>>>> utilization went up by about 30%, resulted in throughput >>>>>>> degradation of this process. >>>>>>> >>>>>>> If EPT disabled, this problem gone. >>>>>>> >>>>>>> I suspect that kvm hypervisor has business with this problem. >>>>>>> Based on above suspect, I want to find the two adjacent versions of >>>>>>> kvm-kmod which triggers this problem or not (e.g. 2.6.39, 3.0-rc1), >>>>>>> and analyze the differences between this two versions, or apply the >>>>>>> patches between this two versions by bisection method, finally find the key patches. >>>>>>> >>>>>>> Any better ideas? >>>>>>> >>>>>>> Thanks, >>>>>>> Zhang Haoyu >>>>>> >>>>>> I've attempted to duplicate this on a number of machines that are as similar to yours as I am able to get my hands on, and so far have not been able to see any performance degradation. And from what I've read in the above links, huge pages do not seem to be part of the problem. >>>>>> >>>>>> So, if you are in a position to bisect the kernel changes, that would probably be the best avenue to pursue in my opinion. >>>>>> >>>>>> Bruce >>>>> >>>>> I found the first bad >>>>> commit([612819c3c6e67bac8fceaa7cc402f13b1b63f7e4] KVM: propagate fault r/w information to gup(), allow read-only memory) which triggers this problem by git bisecting the kvm kernel (download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git) changes. >>>>> >>>>> And, >>>>> git log 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 -n 1 -p > >>>>> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log >>>>> git diff >>>>> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1..612819c3c6e67bac8fceaa7cc4 >>>>> 02f13b1b63f7e4 > 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff >>>>> >>>>> Then, I diffed 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.log and >>>>> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4.diff, >>>>> came to a conclusion that all of the differences between >>>>> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4~1 and >>>>> 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 >>>>> are contributed by no other than 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4, so this commit is the peace-breaker which directly or indirectly causes the degradation. >>>>> >>>>> Does the map_writable flag passed to mmu_set_spte() function have effect on PTE's PAT flag or increase the VMEXITs induced by that guest tried to write read-only memory? >>>>> >>>>> Thanks, >>>>> Zhang Haoyu >>>>> >>>> >>>> There should be no read-only memory maps backing guest RAM. >>>> >>>> Can you confirm map_writable = false is being passed to __direct_map? (this should not happen, for guest RAM). >>>> And if it is false, please capture the associated GFN. >>>> >>> I added below check and printk at the start of __direct_map() at the fist bad commit version, >>> --- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 >>> +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 >>> @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu >>> int pt_write = 0; >>> gfn_t pseudo_gfn; >>> >>> + if (!map_writable) >>> + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); >>> + >>> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { >>> if (iterator.level == level) { >>> unsigned pte_access = ACC_ALL; >>> >>> I virsh-save the VM, and then virsh-restore it, so many GFNs were printed, you can absolutely describe it as flooding. >>> >> The flooding you see happens during migrate to file stage because of dirty >> page tracking. If you clear dmesg after virsh-save you should not see any >> flooding after virsh-restore. I just checked with latest tree, I do not. > > I made a verification again. > I virsh-save the VM, during the saving stage, I run 'dmesg', no GFN printed, maybe the switching from running stage to pause stage takes so short time, > no guest-write happens during this switching period. > After the completion of saving operation, I run 'demsg -c' to clear the buffer all the same, then I virsh-restore the VM, so many GFNs are printed by running 'dmesg', > and I also run 'tail -f /var/log/messages' during the restoring stage, so many GFNs are flooded dynamically too. > I'm sure that the flooding happens during the virsh-restore stage, not the migration stage. > > On VM's normal starting stage, only very few GFNs are printed, shown as below > gfn = 16 > gfn = 604 > gfn = 605 > gfn = 606 > gfn = 607 > gfn = 608 > gfn = 609 > > but on the VM's restoring stage, so many GFNs are printed, taking some examples shown as below, That's really strange. Could you please disable ept and add your trace code to FNAME(fetch)( ), then test again to see what will happen? If there is still have many !rmap_writable cases, please measure the performance to see if it still has regression. Many thanks!
>> The QEMU command line (/var/log/libvirt/qemu/[domain name].log), >> LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ QEMU_AUDIO_DRV=none >> /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu qemu32 >> -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid >> 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults >> -chardev >> socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server,n >> owait -mon chardev=charmonitor,id=monitor,mode=control -rtc >> base=localtime -no-shutdown -device >> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive >> file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cach >> e=none -device >> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id >> =virtio-disk0,bootindex=1 -netdev >> tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device >> virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci.0 >> ,addr=0x3,bootindex=2 -netdev >> tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device >> virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci.0 >> ,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device >> virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci.0 >> ,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device >> virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci.0 >> ,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device >> virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci.0 >> ,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device >> virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci.0 >> ,addr=0x9 -chardev pty,id=charserial0 -device >> isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga >> cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb >> -watchdog-action poweroff -device >> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa >> >Which QEMU version is this? Can you try with e1000 NICs instead of virtio? > This QEMU version is 1.0.0, but I also test QEMU 1.5.2, the same problem exists, including the performance degradation and readonly GFNs' flooding. I tried with e1000 NICs instead of virtio, including the performance degradation and readonly GFNs' flooding, the QEMU version is 1.5.2. No matter e1000 NICs or virtio NICs, the GFNs' flooding is initiated at post-restore stage (i.e. running stage), as soon as the restoring completed, the flooding is starting. Thanks, Zhang Haoyu >-- > Gleb.
>>> The QEMU command line (/var/log/libvirt/qemu/[domain name].log), >>> LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ >>> QEMU_AUDIO_DRV=none >>> /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu >>> qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid >>> 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults >>> -chardev >>> socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server, >>> n owait -mon chardev=charmonitor,id=monitor,mode=control -rtc >>> base=localtime -no-shutdown -device >>> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive >>> file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cac >>> h >>> e=none -device >>> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,i >>> d >>> =virtio-disk0,bootindex=1 -netdev >>> tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device >>> virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci. >>> 0 >>> ,addr=0x3,bootindex=2 -netdev >>> tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device >>> virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci. >>> 0 >>> ,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device >>> virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci. >>> 0 >>> ,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device >>> virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci. >>> 0 >>> ,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device >>> virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci. >>> 0 >>> ,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device >>> virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci. >>> 0 >>> ,addr=0x9 -chardev pty,id=charserial0 -device >>> isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga >>> cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb >>> -watchdog-action poweroff -device >>> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa >>> >>Which QEMU version is this? Can you try with e1000 NICs instead of virtio? >> >This QEMU version is 1.0.0, but I also test QEMU 1.5.2, the same problem exists, including the performance degradation and readonly GFNs' flooding. >I tried with e1000 NICs instead of virtio, including the performance degradation and readonly GFNs' flooding, the QEMU version is 1.5.2. >No matter e1000 NICs or virtio NICs, the GFNs' flooding is initiated at post-restore stage (i.e. running stage), as soon as the restoring completed, the flooding is starting. > >Thanks, >Zhang Haoyu > >>-- >> Gleb. Should we focus on the first bad commit(612819c3c6e67bac8fceaa7cc402f13b1b63f7e4) and the surprising GFNs' flooding? I applied below patch to __direct_map(), @@ -2223,6 +2223,8 @@ static int __direct_map(struct kvm_vcpu int pt_write = 0; gfn_t pseudo_gfn; + map_writable = true; + for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { if (iterator.level == level) { unsigned pte_access = ACC_ALL; and rebuild the kvm-kmod, then re-insmod it. After I started a VM, the host seemed to be abnormal, so many programs cannot be started successfully, segmentation fault is reported. In my opinion, after above patch applied, the commit: 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 should be of no effect, but the test result proved me wrong. Dose the map_writable value's getting process in hva_to_pfn() have effect on the result? Thanks, Zhang Haoyu
On Wed, Aug 07, 2013 at 01:34:41AM +0000, Zhanghaoyu (A) wrote: > >>> The QEMU command line (/var/log/libvirt/qemu/[domain name].log), > >>> LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ > >>> QEMU_AUDIO_DRV=none > >>> /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu > >>> qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid > >>> 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults > >>> -chardev > >>> socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server, > >>> n owait -mon chardev=charmonitor,id=monitor,mode=control -rtc > >>> base=localtime -no-shutdown -device > >>> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive > >>> file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cac > >>> h > >>> e=none -device > >>> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,i > >>> d > >>> =virtio-disk0,bootindex=1 -netdev > >>> tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device > >>> virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x3,bootindex=2 -netdev > >>> tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device > >>> virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device > >>> virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device > >>> virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device > >>> virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device > >>> virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci. > >>> 0 > >>> ,addr=0x9 -chardev pty,id=charserial0 -device > >>> isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga > >>> cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb > >>> -watchdog-action poweroff -device > >>> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa > >>> > >>Which QEMU version is this? Can you try with e1000 NICs instead of virtio? > >> > >This QEMU version is 1.0.0, but I also test QEMU 1.5.2, the same problem exists, including the performance degradation and readonly GFNs' flooding. > >I tried with e1000 NICs instead of virtio, including the performance degradation and readonly GFNs' flooding, the QEMU version is 1.5.2. > >No matter e1000 NICs or virtio NICs, the GFNs' flooding is initiated at post-restore stage (i.e. running stage), as soon as the restoring completed, the flooding is starting. > > > >Thanks, > >Zhang Haoyu > > > >>-- > >> Gleb. > > Should we focus on the first bad commit(612819c3c6e67bac8fceaa7cc402f13b1b63f7e4) and the surprising GFNs' flooding? > Not really. There is no point in debugging very old version compiled with kvm-kmod, there are to many variables in the environment. I cannot reproduce the GFN flooding on upstream, so the problem may be gone, may be a result of kvm-kmod problem or something different in how I invoke qemu. So the best way to proceed is for you to reproduce with upstream version then at least I will be sure that we are using the same code. > I applied below patch to __direct_map(), > @@ -2223,6 +2223,8 @@ static int __direct_map(struct kvm_vcpu > int pt_write = 0; > gfn_t pseudo_gfn; > > + map_writable = true; > + > for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { > if (iterator.level == level) { > unsigned pte_access = ACC_ALL; > and rebuild the kvm-kmod, then re-insmod it. > After I started a VM, the host seemed to be abnormal, so many programs cannot be started successfully, segmentation fault is reported. > In my opinion, after above patch applied, the commit: 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 should be of no effect, but the test result proved me wrong. > Dose the map_writable value's getting process in hva_to_pfn() have effect on the result? > If hva_to_pfn() returns map_writable == false it means that page is mapped as read only on primary MMU, so it should not be mapped writable on secondary MMU either. This should not happen usually. -- Gleb.
>> >>> The QEMU command line (/var/log/libvirt/qemu/[domain name].log), >> >>> LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ >> >>> QEMU_AUDIO_DRV=none >> >>> /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu >> >>> qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 -uuid >> >>> 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults >> >>> -chardev >> >>> socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,server, >> >>> n owait -mon chardev=charmonitor,id=monitor,mode=control -rtc >> >>> base=localtime -no-shutdown -device >> >>> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive >> >>> file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw,cac >> >>> h >> >>> e=none -device >> >>> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,i >> >>> d >> >>> =virtio-disk0,bootindex=1 -netdev >> >>> tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device >> >>> virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x3,bootindex=2 -netdev >> >>> tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device >> >>> virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 -device >> >>> virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 -device >> >>> virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 -device >> >>> virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 -device >> >>> virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci. >> >>> 0 >> >>> ,addr=0x9 -chardev pty,id=charserial0 -device >> >>> isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga >> >>> cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb >> >>> -watchdog-action poweroff -device >> >>> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa >> >>> >> >>Which QEMU version is this? Can you try with e1000 NICs instead of virtio? >> >> >> >This QEMU version is 1.0.0, but I also test QEMU 1.5.2, the same problem exists, including the performance degradation and readonly GFNs' flooding. >> >I tried with e1000 NICs instead of virtio, including the performance degradation and readonly GFNs' flooding, the QEMU version is 1.5.2. >> >No matter e1000 NICs or virtio NICs, the GFNs' flooding is initiated at post-restore stage (i.e. running stage), as soon as the restoring completed, the flooding is starting. >> > >> >Thanks, >> >Zhang Haoyu >> > >> >>-- >> >> Gleb. >> >> Should we focus on the first bad commit(612819c3c6e67bac8fceaa7cc402f13b1b63f7e4) and the surprising GFNs' flooding? >> >Not really. There is no point in debugging very old version compiled >with kvm-kmod, there are to many variables in the environment. I cannot >reproduce the GFN flooding on upstream, so the problem may be gone, may >be a result of kvm-kmod problem or something different in how I invoke >qemu. So the best way to proceed is for you to reproduce with upstream >version then at least I will be sure that we are using the same code. > Thanks, I will test the combos of upstream kvm kernel and upstream qemu. And, the guest os version above I said was wrong, current running guest os is SLES10SP4. Thanks, Zhang Haoyu >> I applied below patch to __direct_map(), >> @@ -2223,6 +2223,8 @@ static int __direct_map(struct kvm_vcpu >> int pt_write = 0; >> gfn_t pseudo_gfn; >> >> + map_writable = true; >> + >> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { >> if (iterator.level == level) { >> unsigned pte_access = ACC_ALL; >> and rebuild the kvm-kmod, then re-insmod it. >> After I started a VM, the host seemed to be abnormal, so many programs cannot be started successfully, segmentation fault is reported. >> In my opinion, after above patch applied, the commit: 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 should be of no effect, but the test result proved me wrong. >> Dose the map_writable value's getting process in hva_to_pfn() have effect on the result? >> >If hva_to_pfn() returns map_writable == false it means that page is >mapped as read only on primary MMU, so it should not be mapped writable >on secondary MMU either. This should not happen usually. > >-- > Gleb.
>>> >>> The QEMU command line (/var/log/libvirt/qemu/[domain name].log), >>> >>> LC_ALL=C PATH=/bin:/sbin:/usr/bin:/usr/sbin HOME=/ >>> >>> QEMU_AUDIO_DRV=none >>> >>> /usr/local/bin/qemu-system-x86_64 -name ATS1 -S -M pc-0.12 -cpu >>> >>> qemu32 -enable-kvm -m 12288 -smp 4,sockets=4,cores=1,threads=1 >>> >>> -uuid >>> >>> 0505ec91-382d-800e-2c79-e5b286eb60b5 -no-user-config -nodefaults >>> >>> -chardev >>> >>> socket,id=charmonitor,path=/var/lib/libvirt/qemu/ATS1.monitor,ser >>> >>> ver, n owait -mon chardev=charmonitor,id=monitor,mode=control >>> >>> -rtc base=localtime -no-shutdown -device >>> >>> piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive >>> >>> file=/opt/ne/vm/ATS1.img,if=none,id=drive-virtio-disk0,format=raw >>> >>> ,cac >>> >>> h >>> >>> e=none -device >>> >>> virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-dis >>> >>> k0,i >>> >>> d >>> >>> =virtio-disk0,bootindex=1 -netdev >>> >>> tap,fd=20,id=hostnet0,vhost=on,vhostfd=21 -device >>> >>> virtio-net-pci,netdev=hostnet0,id=net0,mac=00:e0:fc:00:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x3,bootindex=2 -netdev >>> >>> tap,fd=22,id=hostnet1,vhost=on,vhostfd=23 -device >>> >>> virtio-net-pci,netdev=hostnet1,id=net1,mac=00:e0:fc:01:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x4 -netdev tap,fd=24,id=hostnet2,vhost=on,vhostfd=25 >>> >>> -device virtio-net-pci,netdev=hostnet2,id=net2,mac=00:e0:fc:02:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x5 -netdev tap,fd=26,id=hostnet3,vhost=on,vhostfd=27 >>> >>> -device virtio-net-pci,netdev=hostnet3,id=net3,mac=00:e0:fc:03:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x6 -netdev tap,fd=28,id=hostnet4,vhost=on,vhostfd=29 >>> >>> -device virtio-net-pci,netdev=hostnet4,id=net4,mac=00:e0:fc:0a:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x7 -netdev tap,fd=30,id=hostnet5,vhost=on,vhostfd=31 >>> >>> -device virtio-net-pci,netdev=hostnet5,id=net5,mac=00:e0:fc:0b:0f:00,bus=pci. >>> >>> 0 >>> >>> ,addr=0x9 -chardev pty,id=charserial0 -device >>> >>> isa-serial,chardev=charserial0,id=serial0 -vnc *:0 -k en-us -vga >>> >>> cirrus -device i6300esb,id=watchdog0,bus=pci.0,addr=0xb >>> >>> -watchdog-action poweroff -device >>> >>> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0xa >>> >>> >>> >>Which QEMU version is this? Can you try with e1000 NICs instead of virtio? >>> >> >>> >This QEMU version is 1.0.0, but I also test QEMU 1.5.2, the same problem exists, including the performance degradation and readonly GFNs' flooding. >>> >I tried with e1000 NICs instead of virtio, including the performance degradation and readonly GFNs' flooding, the QEMU version is 1.5.2. >>> >No matter e1000 NICs or virtio NICs, the GFNs' flooding is initiated at post-restore stage (i.e. running stage), as soon as the restoring completed, the flooding is starting. >>> > >>> >Thanks, >>> >Zhang Haoyu >>> > >>> >>-- >>> >> Gleb. >>> >>> Should we focus on the first bad commit(612819c3c6e67bac8fceaa7cc402f13b1b63f7e4) and the surprising GFNs' flooding? >>> >>Not really. There is no point in debugging very old version compiled >>with kvm-kmod, there are to many variables in the environment. I cannot >>reproduce the GFN flooding on upstream, so the problem may be gone, may >>be a result of kvm-kmod problem or something different in how I invoke >>qemu. So the best way to proceed is for you to reproduce with upstream >>version then at least I will be sure that we are using the same code. >> >Thanks, I will test the combos of upstream kvm kernel and upstream qemu. >And, the guest os version above I said was wrong, current running guest os is SLES10SP4. > I tested below combos of qemu and kernel, +-----------------+-----------------+-----------------+ | kvm kernel | QEMU | test result | +-----------------+-----------------+-----------------+ | kvm-3.11-2 | qemu-1.5.2 | GOOD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.0.0 | BAD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.4.0 | BAD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.4.2 | BAD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.5.0-rc0 | GOOD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.5.0 | GOOD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.5.1 | GOOD | +-----------------+-----------------+-----------------+ | SLES11SP2 | qemu-1.5.2 | GOOD | +-----------------+-----------------+-----------------+ NOTE: 1. above kvm-3.11-2 in the table is the whole tag kernel download from https://git.kernel.org/pub/scm/virt/kvm/kvm.git 2. SLES11SP2's kernel version is 3.0.13-0.27 Then I git bisect the qemu changes between qemu-1.4.2 and qemu-1.5.0-rc0 by marking the good version as bad, and the bad version as good, so the first bad commit is just the patch which fixes the degradation problem. +------------+-------------------------------------------+-----------------+-----------------+ | bisect No. | commit | save-restore | migration | +------------+-------------------------------------------+-----------------+-----------------+ | 1 | 03e94e39ce5259efdbdeefa1f249ddb499d57321 | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 2 | 99835e00849369bab726a4dc4ceed1f6f9ed967c | GOOD | GOOD | +------------+-------------------------------------------+-----------------+-----------------+ | 3 | 62e1aeaee4d0450222a0ea43c713b59526e3e0fe | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 4 | 9d9801cf803cdceaa4845fe27150b24d5ab083e6 | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 5 | d76bb73549fcac07524aea5135280ea533a94fd6 | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 6 | d913829f0fd8451abcb1fd9d6dfce5586d9d7e10 | GOOD | GOOD | +------------+-------------------------------------------+-----------------+-----------------+ | 7 | d2f38a0acb0a1c5b7ab7621a32d603d08d513bea | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 8 | e344b8a16de429ada3d9126f26e2a96d71348356 | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 9 | 56ded708ec38e4cb75a7c7357480ca34c0dc6875 | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 10 | 78d07ae7ac74bcc7f79aeefbaff17fb142f44b4d | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 11 | 70c8652bf3c1fea79b7b68864e86926715c49261 | GOOD | GOOD | +------------+-------------------------------------------+-----------------+-----------------+ | 12 | f1c72795af573b24a7da5eb52375c9aba8a37972 | GOOD | GOOD | +------------+-------------------------------------------+-----------------+-----------------+ NOTE: above tests were made on SLES11SP2. So, the commit f1c72795af573b24a7da5eb52375c9aba8a37972 is just the patch which fixes the degradation. Then, I replace SLES11SP2's default kvm-kmod with kvm-kmod-3.6, and applied below patch to __direct_map(), @@ -2599,6 +2599,9 @@ static int __direct_map(struct kvm_vcpu int emulate = 0; gfn_t pseudo_gfn; + if (!map_writable) + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); + for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { if (iterator.level == level) { unsigned pte_access = ACC_ALL; and, I rebuild the kvm-kmod, then re-insmod it, test the adjacent commits again, test results shown as below, +------------+-------------------------------------------+-----------------+-----------------+ | bisect No. | commit | save-restore | migration | +------------+-------------------------------------------+-----------------+-----------------+ | 10 | 78d07ae7ac74bcc7f79aeefbaff17fb142f44b4d | BAD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ | 12 | f1c72795af573b24a7da5eb52375c9aba8a37972 | GOOD | BAD | +------------+-------------------------------------------+-----------------+-----------------+ While testing commit 78d07ae7ac74bcc7f79aeefbaff17fb142f44b4d, as soon as the restoration/migration complete, the GFNs flooding is starting, take some examples shown as below, 2073462 2857203 2073463 2073464 2073465 3218751 2073466 2857206 2857207 2073467 2073468 2857210 2857211 3218752 2857214 2857215 3218753 2857217 2857218 2857221 2857222 3218754 2857225 2857226 3218755 2857229 2857230 2857232 2857233 3218756 2780393 2780394 2857236 2780395 2857237 2780396 2780397 2780398 2780399 2780400 2780401 3218757 2857240 2857241 2857244 3218758 2857247 2857248 2857251 2857252 3218759 2857255 2857256 3218760 2857289 2857290 2857293 2857294 3218761 2857297 2857298 3218762 3218763 3218764 3218765 3218766 3218767 3218768 3218769 3218770 3218771 3218772 but, after a period of time, the flooding rate slowed down. while testing commit f1c72795af573b24a7da5eb52375c9aba8a37972, after restoration, no GFN was printed, and no performance degradation. but as soon as live migration complete, GFNs flooding is starting, and performance degradation also happened. NOTE: The test results of commit f1c72795af573b24a7da5eb52375c9aba8a37972 seemed to be unstable, I will make verification again. >Thanks, >Zhang Haoyu > >>> I applied below patch to __direct_map(), @@ -2223,6 +2223,8 @@ >>> static int __direct_map(struct kvm_vcpu >>> int pt_write = 0; >>> gfn_t pseudo_gfn; >>> >>> + map_writable = true; >>> + >>> for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { >>> if (iterator.level == level) { >>> unsigned pte_access = ACC_ALL; and rebuild >>> the kvm-kmod, then re-insmod it. >>> After I started a VM, the host seemed to be abnormal, so many programs cannot be started successfully, segmentation fault is reported. >>> In my opinion, after above patch applied, the commit: 612819c3c6e67bac8fceaa7cc402f13b1b63f7e4 should be of no effect, but the test result proved me wrong. >>> Dose the map_writable value's getting process in hva_to_pfn() have effect on the result? >>> >>If hva_to_pfn() returns map_writable == false it means that page is >>mapped as read only on primary MMU, so it should not be mapped writable >>on secondary MMU either. This should not happen usually. >> >>-- >> Gleb.
--- kvm-612819c3c6e67bac8fceaa7cc402f13b1b63f7e4/arch/x86/kvm/mmu.c 2013-07-26 18:44:05.000000000 +0800 +++ kvm-612819/arch/x86/kvm/mmu.c 2013-07-31 00:05:48.000000000 +0800 @@ -2223,6 +2223,9 @@ static int __direct_map(struct kvm_vcpu int pt_write = 0; gfn_t pseudo_gfn; + if (!map_writable) + printk(KERN_ERR "%s: %s: gfn = %llu \n", __FILE__, __func__, gfn); + for_each_shadow_entry(vcpu, (u64)gfn << PAGE_SHIFT, iterator) { if (iterator.level == level) { unsigned pte_access = ACC_ALL;