| Message ID | 1448606921-17846-1-git-send-email-den@openvz.org |
|---|---|
| State | New |
| Headers | show |
On 11/27/2015 09:48 AM, Denis V. Lunev wrote: > e1000 driver in Win2k12 is really well rotten. It 100% hangs on shutdown > of UP VM under flood ping. The guest checks card state and reinjects > itself interrupt in a loop. This is fatal for UP machine. > > There is no good way to fix this misbehavior but to kludge it. The > emulation has interrupt throttling register aka ITR which limits > interrupt rate and allows the guest to proceed this phase. > There is no problem with this kludge for Linux guests - it adjust the > value of it itself. > > On the other hand according to the initial research in > commit e9845f0985f088dd01790f4821026df0afba5795 > Author: Vincenzo Maffione <v.maffione@gmail.com> > Date: Fri Aug 2 18:30:52 2013 +0200 > > e1000: add interrupt mitigation support > > ... > > Interrupt mitigation boosts performance when the guest suffers from > an high interrupt rate (i.e. receiving short UDP packets at high packet > rate). For some numerical results see the following link > http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf > > this should also boost performance a bit. > > See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional > details. > > Signed-off-by: Denis V. Lunev <den@openvz.org> > CC: Vincenzo Maffione <v.maffione@gmail.com> > CC: Stefan Hajnoczi <stefanha@redhat.com> > --- > hw/net/e1000.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/hw/net/e1000.c b/hw/net/e1000.c > index c877e06..0af528f 100644 > --- a/hw/net/e1000.c > +++ b/hw/net/e1000.c > @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) > e1000_link_down(d); > } > > + /* Throttle interrupts to allow poor Win 2012 to shutdown */ > + d->mac_reg[ITR] = 250; > + > /* Some guests expect pre-initialized RAH/RAL (AddrValid flag + MACaddr) */ > d->mac_reg[RA] = 0; > d->mac_reg[RA + 1] = E1000_RAH_AV; Intel manual says about ITR that " A initial suggested range is 651-5580 (28Bh - 15CCh)." Should we use something other than 250? :) http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html Den
On 11/27/2015 09:50 AM, Denis V. Lunev wrote: > On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >> e1000 driver in Win2k12 is really well rotten. It 100% hangs on shutdown >> of UP VM under flood ping. The guest checks card state and reinjects >> itself interrupt in a loop. This is fatal for UP machine. >> >> There is no good way to fix this misbehavior but to kludge it. The >> emulation has interrupt throttling register aka ITR which limits >> interrupt rate and allows the guest to proceed this phase. >> There is no problem with this kludge for Linux guests - it adjust the >> value of it itself. >> >> On the other hand according to the initial research in >> commit e9845f0985f088dd01790f4821026df0afba5795 >> Author: Vincenzo Maffione <v.maffione@gmail.com> >> Date: Fri Aug 2 18:30:52 2013 +0200 >> >> e1000: add interrupt mitigation support >> >> ... >> >> Interrupt mitigation boosts performance when the guest suffers from >> an high interrupt rate (i.e. receiving short UDP packets at high >> packet >> rate). For some numerical results see the following link >> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >> >> this should also boost performance a bit. >> >> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >> details. >> >> Signed-off-by: Denis V. Lunev <den@openvz.org> >> CC: Vincenzo Maffione <v.maffione@gmail.com> >> CC: Stefan Hajnoczi <stefanha@redhat.com> >> --- >> hw/net/e1000.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >> index c877e06..0af528f 100644 >> --- a/hw/net/e1000.c >> +++ b/hw/net/e1000.c >> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >> e1000_link_down(d); >> } >> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >> + d->mac_reg[ITR] = 250; >> + >> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag + >> MACaddr) */ >> d->mac_reg[RA] = 0; >> d->mac_reg[RA + 1] = E1000_RAH_AV; > Intel manual says about ITR that " A initial suggested range is > 651-5580 (28Bh - 15CCh)." > Should we use something other than 250? :) > > http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html > > > Den Jason, can you look to this? I have rechecked MAINTAINERs file and found that I have missed you here. Sorry :( Den
On 11/27/2015 07:42 PM, Denis V. Lunev wrote: > On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>> shutdown >>> of UP VM under flood ping. The guest checks card state and reinjects >>> itself interrupt in a loop. This is fatal for UP machine. >>> >>> There is no good way to fix this misbehavior but to kludge it. The >>> emulation has interrupt throttling register aka ITR which limits >>> interrupt rate and allows the guest to proceed this phase. >>> There is no problem with this kludge for Linux guests - it adjust the >>> value of it itself. >>> >>> On the other hand according to the initial research in >>> commit e9845f0985f088dd01790f4821026df0afba5795 >>> Author: Vincenzo Maffione <v.maffione@gmail.com> >>> Date: Fri Aug 2 18:30:52 2013 +0200 >>> >>> e1000: add interrupt mitigation support >>> >>> ... >>> >>> Interrupt mitigation boosts performance when the guest suffers >>> from >>> an high interrupt rate (i.e. receiving short UDP packets at >>> high packet >>> rate). For some numerical results see the following link >>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>> >>> this should also boost performance a bit. >>> >>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >>> details. >>> >>> Signed-off-by: Denis V. Lunev <den@openvz.org> >>> CC: Vincenzo Maffione <v.maffione@gmail.com> >>> CC: Stefan Hajnoczi <stefanha@redhat.com> >>> --- >>> hw/net/e1000.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>> index c877e06..0af528f 100644 >>> --- a/hw/net/e1000.c >>> +++ b/hw/net/e1000.c >>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>> e1000_link_down(d); >>> } >>> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >>> + d->mac_reg[ITR] = 250; >>> + >>> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag >>> + MACaddr) */ >>> d->mac_reg[RA] = 0; >>> d->mac_reg[RA + 1] = E1000_RAH_AV; >> Intel manual says about ITR that " A initial suggested range is >> 651-5580 (28Bh - 15CCh)." >> Should we use something other than 250? :) >> >> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >> >> >> Den > > Jason, can you look to this? > > I have rechecked MAINTAINERs file and found that > I have missed you here. Sorry :( > > Den > No problem. But I have a question. What if ITR is disabled?
On 11/30/2015 08:58 AM, Jason Wang wrote: > > On 11/27/2015 07:42 PM, Denis V. Lunev wrote: >> On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >>> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>>> shutdown >>>> of UP VM under flood ping. The guest checks card state and reinjects >>>> itself interrupt in a loop. This is fatal for UP machine. >>>> >>>> There is no good way to fix this misbehavior but to kludge it. The >>>> emulation has interrupt throttling register aka ITR which limits >>>> interrupt rate and allows the guest to proceed this phase. >>>> There is no problem with this kludge for Linux guests - it adjust the >>>> value of it itself. >>>> >>>> On the other hand according to the initial research in >>>> commit e9845f0985f088dd01790f4821026df0afba5795 >>>> Author: Vincenzo Maffione <v.maffione@gmail.com> >>>> Date: Fri Aug 2 18:30:52 2013 +0200 >>>> >>>> e1000: add interrupt mitigation support >>>> >>>> ... >>>> >>>> Interrupt mitigation boosts performance when the guest suffers >>>> from >>>> an high interrupt rate (i.e. receiving short UDP packets at >>>> high packet >>>> rate). For some numerical results see the following link >>>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>>> >>>> this should also boost performance a bit. >>>> >>>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >>>> details. >>>> >>>> Signed-off-by: Denis V. Lunev <den@openvz.org> >>>> CC: Vincenzo Maffione <v.maffione@gmail.com> >>>> CC: Stefan Hajnoczi <stefanha@redhat.com> >>>> --- >>>> hw/net/e1000.c | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>>> index c877e06..0af528f 100644 >>>> --- a/hw/net/e1000.c >>>> +++ b/hw/net/e1000.c >>>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>>> e1000_link_down(d); >>>> } >>>> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >>>> + d->mac_reg[ITR] = 250; >>>> + >>>> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag >>>> + MACaddr) */ >>>> d->mac_reg[RA] = 0; >>>> d->mac_reg[RA + 1] = E1000_RAH_AV; >>> Intel manual says about ITR that " A initial suggested range is >>> 651-5580 (28Bh - 15CCh)." >>> Should we use something other than 250? :) >>> >>> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >>> >>> >>> Den >> Jason, can you look to this? >> >> I have rechecked MAINTAINERs file and found that >> I have missed you here. Sorry :( >> >> Den >> > No problem. > > But I have a question. What if ITR is disabled? > On behalf of guest I do not think that this is really true. In this case the guest should set it to a real value and after that clear it. This is not the case - my patch applies on a reset only, i.e. the guest do not care at all on this and the value lives "as is". I think that real card behaves in a similar way, it could not generate interrupts with the speed of any hypervisor, i.e. there is natural limitation which allows to bypass this problem or there is a default value. On behalf of QEMU the question is still here. Fortunately the handle (mitigation flag) is on by default. I think that it exists to preserve compatibility with QEMU 1.6 In a real life nobody will turn it off until the person is know what he is doing ;) Den
On 11/30/2015 02:22 PM, Denis V. Lunev wrote: > On 11/30/2015 08:58 AM, Jason Wang wrote: >> >> On 11/27/2015 07:42 PM, Denis V. Lunev wrote: >>> On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >>>> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>>>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>>>> shutdown >>>>> of UP VM under flood ping. The guest checks card state and reinjects >>>>> itself interrupt in a loop. This is fatal for UP machine. >>>>> >>>>> There is no good way to fix this misbehavior but to kludge it. The >>>>> emulation has interrupt throttling register aka ITR which limits >>>>> interrupt rate and allows the guest to proceed this phase. >>>>> There is no problem with this kludge for Linux guests - it adjust the >>>>> value of it itself. >>>>> >>>>> On the other hand according to the initial research in >>>>> commit e9845f0985f088dd01790f4821026df0afba5795 >>>>> Author: Vincenzo Maffione <v.maffione@gmail.com> >>>>> Date: Fri Aug 2 18:30:52 2013 +0200 >>>>> >>>>> e1000: add interrupt mitigation support >>>>> >>>>> ... >>>>> >>>>> Interrupt mitigation boosts performance when the guest suffers >>>>> from >>>>> an high interrupt rate (i.e. receiving short UDP packets at >>>>> high packet >>>>> rate). For some numerical results see the following link >>>>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>>>> >>>>> this should also boost performance a bit. >>>>> >>>>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >>>>> details. >>>>> >>>>> Signed-off-by: Denis V. Lunev <den@openvz.org> >>>>> CC: Vincenzo Maffione <v.maffione@gmail.com> >>>>> CC: Stefan Hajnoczi <stefanha@redhat.com> >>>>> --- >>>>> hw/net/e1000.c | 3 +++ >>>>> 1 file changed, 3 insertions(+) >>>>> >>>>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>>>> index c877e06..0af528f 100644 >>>>> --- a/hw/net/e1000.c >>>>> +++ b/hw/net/e1000.c >>>>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>>>> e1000_link_down(d); >>>>> } >>>>> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >>>>> + d->mac_reg[ITR] = 250; >>>>> + >>>>> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag >>>>> + MACaddr) */ >>>>> d->mac_reg[RA] = 0; >>>>> d->mac_reg[RA + 1] = E1000_RAH_AV; >>>> Intel manual says about ITR that " A initial suggested range is >>>> 651-5580 (28Bh - 15CCh)." >>>> Should we use something other than 250? :) >>>> >>>> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >>>> >>>> >>>> >>>> Den >>> Jason, can you look to this? >>> >>> I have rechecked MAINTAINERs file and found that >>> I have missed you here. Sorry :( >>> >>> Den >>> >> No problem. >> >> But I have a question. What if ITR is disabled? >> > > On behalf of guest I do not think that this is really true. > In this case the guest should set it to a real value and > after that clear it. This is not the case - my patch > applies on a reset only, i.e. the guest do not care at all > on this and the value lives "as is". I think that real card > behaves in a similar way, it could not generate interrupts > with the speed of any hypervisor, i.e. there is natural > limitation which allows to bypass this problem or there > is a default value. > > On behalf of QEMU the question is still here. Fortunately > the handle (mitigation flag) is on by default. I think that > it exists to preserve compatibility with QEMU 1.6 > In a real life nobody will turn it off until the person is > know what he is doing ;) > > Den Ok, apply to my -net with minor tweaks and adding a TODO in the comment. We've met several similar issues in the past, need to consider a complete solution in the future otherwise we may still hit something like this in the future. Thanks
On 12/01/2015 06:31 AM, Jason Wang wrote: > > On 11/30/2015 02:22 PM, Denis V. Lunev wrote: >> On 11/30/2015 08:58 AM, Jason Wang wrote: >>> On 11/27/2015 07:42 PM, Denis V. Lunev wrote: >>>> On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >>>>> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>>>>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>>>>> shutdown >>>>>> of UP VM under flood ping. The guest checks card state and reinjects >>>>>> itself interrupt in a loop. This is fatal for UP machine. >>>>>> >>>>>> There is no good way to fix this misbehavior but to kludge it. The >>>>>> emulation has interrupt throttling register aka ITR which limits >>>>>> interrupt rate and allows the guest to proceed this phase. >>>>>> There is no problem with this kludge for Linux guests - it adjust the >>>>>> value of it itself. >>>>>> >>>>>> On the other hand according to the initial research in >>>>>> commit e9845f0985f088dd01790f4821026df0afba5795 >>>>>> Author: Vincenzo Maffione <v.maffione@gmail.com> >>>>>> Date: Fri Aug 2 18:30:52 2013 +0200 >>>>>> >>>>>> e1000: add interrupt mitigation support >>>>>> >>>>>> ... >>>>>> >>>>>> Interrupt mitigation boosts performance when the guest suffers >>>>>> from >>>>>> an high interrupt rate (i.e. receiving short UDP packets at >>>>>> high packet >>>>>> rate). For some numerical results see the following link >>>>>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>>>>> >>>>>> this should also boost performance a bit. >>>>>> >>>>>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional >>>>>> details. >>>>>> >>>>>> Signed-off-by: Denis V. Lunev <den@openvz.org> >>>>>> CC: Vincenzo Maffione <v.maffione@gmail.com> >>>>>> CC: Stefan Hajnoczi <stefanha@redhat.com> >>>>>> --- >>>>>> hw/net/e1000.c | 3 +++ >>>>>> 1 file changed, 3 insertions(+) >>>>>> >>>>>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>>>>> index c877e06..0af528f 100644 >>>>>> --- a/hw/net/e1000.c >>>>>> +++ b/hw/net/e1000.c >>>>>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>>>>> e1000_link_down(d); >>>>>> } >>>>>> + /* Throttle interrupts to allow poor Win 2012 to shutdown */ >>>>>> + d->mac_reg[ITR] = 250; >>>>>> + >>>>>> /* Some guests expect pre-initialized RAH/RAL (AddrValid flag >>>>>> + MACaddr) */ >>>>>> d->mac_reg[RA] = 0; >>>>>> d->mac_reg[RA + 1] = E1000_RAH_AV; >>>>> Intel manual says about ITR that " A initial suggested range is >>>>> 651-5580 (28Bh - 15CCh)." >>>>> Should we use something other than 250? :) >>>>> >>>>> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >>>>> >>>>> >>>>> >>>>> Den >>>> Jason, can you look to this? >>>> >>>> I have rechecked MAINTAINERs file and found that >>>> I have missed you here. Sorry :( >>>> >>>> Den >>>> >>> No problem. >>> >>> But I have a question. What if ITR is disabled? >>> >> On behalf of guest I do not think that this is really true. >> In this case the guest should set it to a real value and >> after that clear it. This is not the case - my patch >> applies on a reset only, i.e. the guest do not care at all >> on this and the value lives "as is". I think that real card >> behaves in a similar way, it could not generate interrupts >> with the speed of any hypervisor, i.e. there is natural >> limitation which allows to bypass this problem or there >> is a default value. >> >> On behalf of QEMU the question is still here. Fortunately >> the handle (mitigation flag) is on by default. I think that >> it exists to preserve compatibility with QEMU 1.6 >> In a real life nobody will turn it off until the person is >> know what he is doing ;) >> >> Den > Ok, apply to my -net with minor tweaks and adding a TODO in the comment. > > We've met several similar issues in the past, need to consider a > complete solution in the future otherwise we may still hit something > like this in the future. > > Thanks thank you. Can you pls clarify, will it go to 2.5 or no? Den
On 12/01/2015 05:38 PM, Denis V. Lunev wrote: > On 12/01/2015 06:31 AM, Jason Wang wrote: >> >> On 11/30/2015 02:22 PM, Denis V. Lunev wrote: >>> On 11/30/2015 08:58 AM, Jason Wang wrote: >>>> On 11/27/2015 07:42 PM, Denis V. Lunev wrote: >>>>> On 11/27/2015 09:50 AM, Denis V. Lunev wrote: >>>>>> On 11/27/2015 09:48 AM, Denis V. Lunev wrote: >>>>>>> e1000 driver in Win2k12 is really well rotten. It 100% hangs on >>>>>>> shutdown >>>>>>> of UP VM under flood ping. The guest checks card state and >>>>>>> reinjects >>>>>>> itself interrupt in a loop. This is fatal for UP machine. >>>>>>> >>>>>>> There is no good way to fix this misbehavior but to kludge it. The >>>>>>> emulation has interrupt throttling register aka ITR which limits >>>>>>> interrupt rate and allows the guest to proceed this phase. >>>>>>> There is no problem with this kludge for Linux guests - it >>>>>>> adjust the >>>>>>> value of it itself. >>>>>>> >>>>>>> On the other hand according to the initial research in >>>>>>> commit e9845f0985f088dd01790f4821026df0afba5795 >>>>>>> Author: Vincenzo Maffione <v.maffione@gmail.com> >>>>>>> Date: Fri Aug 2 18:30:52 2013 +0200 >>>>>>> >>>>>>> e1000: add interrupt mitigation support >>>>>>> >>>>>>> ... >>>>>>> >>>>>>> Interrupt mitigation boosts performance when the guest >>>>>>> suffers >>>>>>> from >>>>>>> an high interrupt rate (i.e. receiving short UDP packets at >>>>>>> high packet >>>>>>> rate). For some numerical results see the following link >>>>>>> http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf >>>>>>> >>>>>>> this should also boost performance a bit. >>>>>>> >>>>>>> See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for >>>>>>> additional >>>>>>> details. >>>>>>> >>>>>>> Signed-off-by: Denis V. Lunev <den@openvz.org> >>>>>>> CC: Vincenzo Maffione <v.maffione@gmail.com> >>>>>>> CC: Stefan Hajnoczi <stefanha@redhat.com> >>>>>>> --- >>>>>>> hw/net/e1000.c | 3 +++ >>>>>>> 1 file changed, 3 insertions(+) >>>>>>> >>>>>>> diff --git a/hw/net/e1000.c b/hw/net/e1000.c >>>>>>> index c877e06..0af528f 100644 >>>>>>> --- a/hw/net/e1000.c >>>>>>> +++ b/hw/net/e1000.c >>>>>>> @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) >>>>>>> e1000_link_down(d); >>>>>>> } >>>>>>> + /* Throttle interrupts to allow poor Win 2012 to >>>>>>> shutdown */ >>>>>>> + d->mac_reg[ITR] = 250; >>>>>>> + >>>>>>> /* Some guests expect pre-initialized RAH/RAL (AddrValid >>>>>>> flag >>>>>>> + MACaddr) */ >>>>>>> d->mac_reg[RA] = 0; >>>>>>> d->mac_reg[RA + 1] = E1000_RAH_AV; >>>>>> Intel manual says about ITR that " A initial suggested range is >>>>>> 651-5580 (28Bh - 15CCh)." >>>>>> Should we use something other than 250? :) >>>>>> >>>>>> http://www.intel.com/content/www/us/en/embedded/products/networking/pci-pci-x-family-gbe-controllers-software-dev-manual.html >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Den >>>>> Jason, can you look to this? >>>>> >>>>> I have rechecked MAINTAINERs file and found that >>>>> I have missed you here. Sorry :( >>>>> >>>>> Den >>>>> >>>> No problem. >>>> >>>> But I have a question. What if ITR is disabled? >>>> >>> On behalf of guest I do not think that this is really true. >>> In this case the guest should set it to a real value and >>> after that clear it. This is not the case - my patch >>> applies on a reset only, i.e. the guest do not care at all >>> on this and the value lives "as is". I think that real card >>> behaves in a similar way, it could not generate interrupts >>> with the speed of any hypervisor, i.e. there is natural >>> limitation which allows to bypass this problem or there >>> is a default value. >>> >>> On behalf of QEMU the question is still here. Fortunately >>> the handle (mitigation flag) is on by default. I think that >>> it exists to preserve compatibility with QEMU 1.6 >>> In a real life nobody will turn it off until the person is >>> know what he is doing ;) >>> >>> Den >> Ok, apply to my -net with minor tweaks and adding a TODO in the comment. >> >> We've met several similar issues in the past, need to consider a >> complete solution in the future otherwise we may still hit something >> like this in the future. >> >> Thanks > thank you. > > Can you pls clarify, will it go to 2.5 or no? > > Den It will go to 2.5. Plan to include this in my last pull request for 2.5. Thanks
On 2 December 2015 at 05:06, Jason Wang <jasowang@redhat.com> wrote:
> It will go to 2.5. Plan to include this in my last pull request for 2.5.
Are you planning to send that pullreq today?
thanks
-- PMM
diff --git a/hw/net/e1000.c b/hw/net/e1000.c index c877e06..0af528f 100644 --- a/hw/net/e1000.c +++ b/hw/net/e1000.c @@ -447,6 +447,9 @@ static void e1000_reset(void *opaque) e1000_link_down(d); } + /* Throttle interrupts to allow poor Win 2012 to shutdown */ + d->mac_reg[ITR] = 250; + /* Some guests expect pre-initialized RAH/RAL (AddrValid flag + MACaddr) */ d->mac_reg[RA] = 0; d->mac_reg[RA + 1] = E1000_RAH_AV;
e1000 driver in Win2k12 is really well rotten. It 100% hangs on shutdown of UP VM under flood ping. The guest checks card state and reinjects itself interrupt in a loop. This is fatal for UP machine. There is no good way to fix this misbehavior but to kludge it. The emulation has interrupt throttling register aka ITR which limits interrupt rate and allows the guest to proceed this phase. There is no problem with this kludge for Linux guests - it adjust the value of it itself. On the other hand according to the initial research in commit e9845f0985f088dd01790f4821026df0afba5795 Author: Vincenzo Maffione <v.maffione@gmail.com> Date: Fri Aug 2 18:30:52 2013 +0200 e1000: add interrupt mitigation support ... Interrupt mitigation boosts performance when the guest suffers from an high interrupt rate (i.e. receiving short UDP packets at high packet rate). For some numerical results see the following link http://info.iet.unipi.it/~luigi/papers/20130520-rizzo-vm.pdf this should also boost performance a bit. See https://bugzilla.redhat.com/show_bug.cgi?id=874406 for additional details. Signed-off-by: Denis V. Lunev <den@openvz.org> CC: Vincenzo Maffione <v.maffione@gmail.com> CC: Stefan Hajnoczi <stefanha@redhat.com> --- hw/net/e1000.c | 3 +++ 1 file changed, 3 insertions(+)