| Message ID | 20230529123101.411267-1-zhao1.liu@linux.intel.com |
|---|---|
| Headers | show |
| Series | Support smp.clusters for x86 | expand |
Hi Yongwei, I missed cc you... On Mon, May 29, 2023 at 08:30:44PM +0800, Zhao Liu wrote: > Date: Mon, 29 May 2023 20:30:44 +0800 > From: Zhao Liu <zhao1.liu@linux.intel.com> > Subject: [PATCH v2 00/17] Support smp.clusters for x86 > X-Mailer: git-send-email 2.34.1 > > From: Zhao Liu <zhao1.liu@intel.com> > > Hi list, > > This is the our v2 patch series, rebased on the master branch at the > commit ac84b57b4d74 ("Merge tag 'for-upstream' of > https://gitlab.com/bonzini/qemu into staging"). > > Comparing with v1 [1], v2 mainly reorganizes patches and does some > cleanup. > > This series add the cluster support for x86 PC machine, which allows > x86 can use smp.clusters to configure the modlue level CPU topology > of x86. > > And since the compatibility issue (see section: ## Why not share L2 > cache in cluster directly), this series also introduce a new command > to adjust the topology of the x86 L2 cache. > > Welcome your comments! > > > # Backgroud > > The "clusters" parameter in "smp" is introduced by ARM [2], but x86 > hasn't supported it. > > At present, x86 defaults L2 cache is shared in one core, but this is > not enough. There're some platforms that multiple cores share the > same L2 cache, e.g., Alder Lake-P shares L2 cache for one module of > Atom cores [3], that is, every four Atom cores shares one L2 cache. > Therefore, we need the new CPU topology level (cluster/module). > > Another reason is for hybrid architecture. cluster support not only > provides another level of topology definition in x86, but would aslo > provide required code change for future our hybrid topology support. > > > # Overview > > ## Introduction of module level for x86 > > "cluster" in smp is the CPU topology level which is between "core" and > die. > > For x86, the "cluster" in smp is corresponding to the module level [4], > which is above the core level. So use the "module" other than "cluster" > in x86 code. > > And please note that x86 already has a cpu topology level also named > "cluster" [4], this level is at the upper level of the package. Here, > the cluster in x86 cpu topology is completely different from the > "clusters" as the smp parameter. After the module level is introduced, > the cluster as the smp parameter will actually refer to the module level > of x86. > > > ## Why not share L2 cache in cluster directly > > Though "clusters" was introduced to help define L2 cache topology > [2], using cluster to define x86's L2 cache topology will cause the > compatibility problem: > > Currently, x86 defaults that the L2 cache is shared in one core, which > actually implies a default setting "cores per L2 cache is 1" and > therefore implicitly defaults to having as many L2 caches as cores. > > For example (i386 PC machine): > -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) > > Considering the topology of the L2 cache, this (*) implicitly means "1 > core per L2 cache" and "2 L2 caches per die". > > If we use cluster to configure L2 cache topology with the new default > setting "clusters per L2 cache is 1", the above semantics will change > to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 > cores per L2 cache". > > So the same command (*) will cause changes in the L2 cache topology, > further affecting the performance of the virtual machine. > > Therefore, x86 should only treat cluster as a cpu topology level and > avoid using it to change L2 cache by default for compatibility. > > > ## module level in CPUID > > Currently, we don't expose module level in CPUID.1FH because currently > linux (v6.2-rc6) doesn't support module level. And exposing module and > die levels at the same time in CPUID.1FH will cause linux to calculate > wrong die_id. The module level should be exposed until the real machine > has the module level in CPUID.1FH. > > We can configure CPUID.04H.02H (L2 cache topology) with module level by > a new command: > > "-cpu,x-l2-cache-topo=cluster" > > More information about this command, please see the section: "## New > property: x-l2-cache-topo". > > > ## New cache topology info in CPUCacheInfo > > Currently, by default, the cache topology is encoded as: > 1. i/d cache is shared in one core. > 2. L2 cache is shared in one core. > 3. L3 cache is shared in one die. > > This default general setting has caused a misunderstanding, that is, the > cache topology is completely equated with a specific cpu topology, such > as the connection between L2 cache and core level, and the connection > between L3 cache and die level. > > In fact, the settings of these topologies depend on the specific > platform and are not static. For example, on Alder Lake-P, every > four Atom cores share the same L2 cache [2]. > > Thus, in this patch set, we explicitly define the corresponding cache > topology for different cpu models and this has two benefits: > 1. Easy to expand to new CPU models in the future, which has different > cache topology. > 2. It can easily support custom cache topology by some command (e.g., > x-l2-cache-topo). > > > ## New property: x-l2-cache-topo > > The property l2-cache-topo will be used to change the L2 cache topology > in CPUID.04H. > > Now it allows user to set the L2 cache is shared in core level or > cluster level. > > If user passes "-cpu x-l2-cache-topo=[core|cluster]" then older L2 cache > topology will be overrided by the new topology setting. > > Since CPUID.04H is used by intel cpus, this property is available on > intel cpus as for now. > > When necessary, it can be extended to CPUID[0x8000001D] for amd cpus. > > > # Patch description > > patch 1-2 Cleanups about coding style and test name. > > patch 3-4,15 Fixes about x86 topology, intel l1 cache topology and amd > cache topology encoding. > > patch 5-6 Cleanups about topology related CPUID encoding and QEMU > topology variables. > > patch 7-12 Add the module as the new CPU topology level in x86, and it > is corresponding to the cluster level in generic code. > > patch 13,14,16 Add cache topology infomation in cache models. > > patch 17 Introduce a new command to configure L2 cache topology. > > > [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg03184.html > [2]: https://patchew.org/QEMU/20211228092221.21068-1-wangyanan55@huawei.com/ > [3]: https://www.intel.com/content/www/us/en/products/platforms/details/alder-lake-p.html > [4]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. > > Best Regards, > Zhao Could you please attach the test results? Thanks, Zhao > > --- > Changelog: > > Changes since v1: > * Reordered patches. (Yanan) > * Deprecated the patch to fix comment of machine_parse_smp_config(). > (Yanan) > * Rename test-x86-cpuid.c to test-x86-topo.c. (Yanan) > * Split the intel's l1 cache topology fix into a new separate patch. > (Yanan) > * Combined module_id and APIC ID for module level support into one > patch. (Yanan) > * Make cache_into_passthrough case of cpuid 0x04 leaf in > * cpu_x86_cpuid() use max_processor_ids_for_cache() and > max_core_ids_in_package() to encode CPUID[4]. (Yanan) > * Add the prefix "CPU_TOPO_LEVEL_*" for CPU topology level names. > (Yanan) > * Rename the "INVALID" level to "CPU_TOPO_LEVEL_UNKNOW". (Yanan) > > --- > Zhao Liu (10): > i386: Fix comment style in topology.h > tests: Rename test-x86-cpuid.c to test-x86-topo.c > i386/cpu: Fix i/d-cache topology to core level for Intel CPU > i386/cpu: Use APIC ID offset to encode cache topo in CPUID[4] > i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() > i386: Add cache topology info in CPUCacheInfo > i386: Use CPUCacheInfo.share_level to encode CPUID[4] > i386: Fix NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14] > i386: Use CPUCacheInfo.share_level to encode > CPUID[0x8000001D].EAX[bits 25:14] > i386: Add new property to control L2 cache topo in CPUID.04H > > Zhuocheng Ding (7): > softmmu: Fix CPUSTATE.nr_cores' calculation > i386: Introduce module-level cpu topology to CPUX86State > i386: Support modules_per_die in X86CPUTopoInfo > i386: Support module_id in X86CPUTopoIDs > i386/cpu: Introduce cluster-id to X86CPU > tests: Add test case of APIC ID for module level parsing > hw/i386/pc: Support smp.clusters for x86 PC machine > > MAINTAINERS | 2 +- > hw/i386/pc.c | 1 + > hw/i386/x86.c | 49 +++++- > include/hw/core/cpu.h | 2 +- > include/hw/i386/topology.h | 68 +++++--- > qemu-options.hx | 10 +- > softmmu/cpus.c | 2 +- > target/i386/cpu.c | 158 ++++++++++++++---- > target/i386/cpu.h | 25 +++ > tests/unit/meson.build | 4 +- > .../{test-x86-cpuid.c => test-x86-topo.c} | 58 ++++--- > 11 files changed, 280 insertions(+), 99 deletions(-) > rename tests/unit/{test-x86-cpuid.c => test-x86-topo.c} (73%) > > -- > 2.34.1 >
> On Mon, May 29, 2023 at 08:30:44PM +0800, Zhao Liu wrote: > > Date: Mon, 29 May 2023 20:30:44 +0800 > > From: Zhao Liu <zhao1.liu@linux.intel.com> > > Subject: [PATCH v2 00/17] Support smp.clusters for x86 > > X-Mailer: git-send-email 2.34.1 > > > > From: Zhao Liu <zhao1.liu@intel.com> > > > > Hi list, > > > > This is the our v2 patch series, rebased on the master branch at the > > commit ac84b57b4d74 ("Merge tag 'for-upstream' of > > https://gitlab.com/bonzini/qemu into staging"). > > > > Comparing with v1 [1], v2 mainly reorganizes patches and does some > > cleanup. > > > > This series add the cluster support for x86 PC machine, which allows > > x86 can use smp.clusters to configure the modlue level CPU topology of > > x86. > > > > And since the compatibility issue (see section: ## Why not share L2 > > cache in cluster directly), this series also introduce a new command > > to adjust the topology of the x86 L2 cache. > > > > Welcome your comments! > > > > [snip] > > Could you please attach the test results? > Tested module level APID 'test-x86-topo' cases and 'x-l2-cache-topo' based on CPUID on Intel platform. Result looks good hence, Tested-by: Yongwei Ma <yongwei.ma@intel.com> Best Regards, Yongwei Ma
On Mon, May 29, 2023 at 08:30:44PM +0800, Zhao Liu wrote: > From: Zhao Liu <zhao1.liu@intel.com> > > Hi list, > > This is the our v2 patch series, rebased on the master branch at the > commit ac84b57b4d74 ("Merge tag 'for-upstream' of > https://gitlab.com/bonzini/qemu into staging"). > > Comparing with v1 [1], v2 mainly reorganizes patches and does some > cleanup. > > This series add the cluster support for x86 PC machine, which allows > x86 can use smp.clusters to configure the modlue level CPU topology > of x86. > > And since the compatibility issue (see section: ## Why not share L2 > cache in cluster directly), this series also introduce a new command > to adjust the topology of the x86 L2 cache. > > Welcome your comments! PC things: Acked-by: Michael S. Tsirkin <mst@redhat.com> > > # Backgroud > > The "clusters" parameter in "smp" is introduced by ARM [2], but x86 > hasn't supported it. > > At present, x86 defaults L2 cache is shared in one core, but this is > not enough. There're some platforms that multiple cores share the > same L2 cache, e.g., Alder Lake-P shares L2 cache for one module of > Atom cores [3], that is, every four Atom cores shares one L2 cache. > Therefore, we need the new CPU topology level (cluster/module). > > Another reason is for hybrid architecture. cluster support not only > provides another level of topology definition in x86, but would aslo > provide required code change for future our hybrid topology support. > > > # Overview > > ## Introduction of module level for x86 > > "cluster" in smp is the CPU topology level which is between "core" and > die. > > For x86, the "cluster" in smp is corresponding to the module level [4], > which is above the core level. So use the "module" other than "cluster" > in x86 code. > > And please note that x86 already has a cpu topology level also named > "cluster" [4], this level is at the upper level of the package. Here, > the cluster in x86 cpu topology is completely different from the > "clusters" as the smp parameter. After the module level is introduced, > the cluster as the smp parameter will actually refer to the module level > of x86. > > > ## Why not share L2 cache in cluster directly > > Though "clusters" was introduced to help define L2 cache topology > [2], using cluster to define x86's L2 cache topology will cause the > compatibility problem: > > Currently, x86 defaults that the L2 cache is shared in one core, which > actually implies a default setting "cores per L2 cache is 1" and > therefore implicitly defaults to having as many L2 caches as cores. > > For example (i386 PC machine): > -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) > > Considering the topology of the L2 cache, this (*) implicitly means "1 > core per L2 cache" and "2 L2 caches per die". > > If we use cluster to configure L2 cache topology with the new default > setting "clusters per L2 cache is 1", the above semantics will change > to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 > cores per L2 cache". > > So the same command (*) will cause changes in the L2 cache topology, > further affecting the performance of the virtual machine. > > Therefore, x86 should only treat cluster as a cpu topology level and > avoid using it to change L2 cache by default for compatibility. > > > ## module level in CPUID > > Currently, we don't expose module level in CPUID.1FH because currently > linux (v6.2-rc6) doesn't support module level. And exposing module and > die levels at the same time in CPUID.1FH will cause linux to calculate > wrong die_id. The module level should be exposed until the real machine > has the module level in CPUID.1FH. > > We can configure CPUID.04H.02H (L2 cache topology) with module level by > a new command: > > "-cpu,x-l2-cache-topo=cluster" > > More information about this command, please see the section: "## New > property: x-l2-cache-topo". > > > ## New cache topology info in CPUCacheInfo > > Currently, by default, the cache topology is encoded as: > 1. i/d cache is shared in one core. > 2. L2 cache is shared in one core. > 3. L3 cache is shared in one die. > > This default general setting has caused a misunderstanding, that is, the > cache topology is completely equated with a specific cpu topology, such > as the connection between L2 cache and core level, and the connection > between L3 cache and die level. > > In fact, the settings of these topologies depend on the specific > platform and are not static. For example, on Alder Lake-P, every > four Atom cores share the same L2 cache [2]. > > Thus, in this patch set, we explicitly define the corresponding cache > topology for different cpu models and this has two benefits: > 1. Easy to expand to new CPU models in the future, which has different > cache topology. > 2. It can easily support custom cache topology by some command (e.g., > x-l2-cache-topo). > > > ## New property: x-l2-cache-topo > > The property l2-cache-topo will be used to change the L2 cache topology > in CPUID.04H. > > Now it allows user to set the L2 cache is shared in core level or > cluster level. > > If user passes "-cpu x-l2-cache-topo=[core|cluster]" then older L2 cache > topology will be overrided by the new topology setting. > > Since CPUID.04H is used by intel cpus, this property is available on > intel cpus as for now. > > When necessary, it can be extended to CPUID[0x8000001D] for amd cpus. > > > # Patch description > > patch 1-2 Cleanups about coding style and test name. > > patch 3-4,15 Fixes about x86 topology, intel l1 cache topology and amd > cache topology encoding. > > patch 5-6 Cleanups about topology related CPUID encoding and QEMU > topology variables. > > patch 7-12 Add the module as the new CPU topology level in x86, and it > is corresponding to the cluster level in generic code. > > patch 13,14,16 Add cache topology infomation in cache models. > > patch 17 Introduce a new command to configure L2 cache topology. > > > [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg03184.html > [2]: https://patchew.org/QEMU/20211228092221.21068-1-wangyanan55@huawei.com/ > [3]: https://www.intel.com/content/www/us/en/products/platforms/details/alder-lake-p.html > [4]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. > > Best Regards, > Zhao > > --- > Changelog: > > Changes since v1: > * Reordered patches. (Yanan) > * Deprecated the patch to fix comment of machine_parse_smp_config(). > (Yanan) > * Rename test-x86-cpuid.c to test-x86-topo.c. (Yanan) > * Split the intel's l1 cache topology fix into a new separate patch. > (Yanan) > * Combined module_id and APIC ID for module level support into one > patch. (Yanan) > * Make cache_into_passthrough case of cpuid 0x04 leaf in > * cpu_x86_cpuid() use max_processor_ids_for_cache() and > max_core_ids_in_package() to encode CPUID[4]. (Yanan) > * Add the prefix "CPU_TOPO_LEVEL_*" for CPU topology level names. > (Yanan) > * Rename the "INVALID" level to "CPU_TOPO_LEVEL_UNKNOW". (Yanan) > > --- > Zhao Liu (10): > i386: Fix comment style in topology.h > tests: Rename test-x86-cpuid.c to test-x86-topo.c > i386/cpu: Fix i/d-cache topology to core level for Intel CPU > i386/cpu: Use APIC ID offset to encode cache topo in CPUID[4] > i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() > i386: Add cache topology info in CPUCacheInfo > i386: Use CPUCacheInfo.share_level to encode CPUID[4] > i386: Fix NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14] > i386: Use CPUCacheInfo.share_level to encode > CPUID[0x8000001D].EAX[bits 25:14] > i386: Add new property to control L2 cache topo in CPUID.04H > > Zhuocheng Ding (7): > softmmu: Fix CPUSTATE.nr_cores' calculation > i386: Introduce module-level cpu topology to CPUX86State > i386: Support modules_per_die in X86CPUTopoInfo > i386: Support module_id in X86CPUTopoIDs > i386/cpu: Introduce cluster-id to X86CPU > tests: Add test case of APIC ID for module level parsing > hw/i386/pc: Support smp.clusters for x86 PC machine > > MAINTAINERS | 2 +- > hw/i386/pc.c | 1 + > hw/i386/x86.c | 49 +++++- > include/hw/core/cpu.h | 2 +- > include/hw/i386/topology.h | 68 +++++--- > qemu-options.hx | 10 +- > softmmu/cpus.c | 2 +- > target/i386/cpu.c | 158 ++++++++++++++---- > target/i386/cpu.h | 25 +++ > tests/unit/meson.build | 4 +- > .../{test-x86-cpuid.c => test-x86-topo.c} | 58 ++++--- > 11 files changed, 280 insertions(+), 99 deletions(-) > rename tests/unit/{test-x86-cpuid.c => test-x86-topo.c} (73%) > > -- > 2.34.1
On Thu, Jun 22, 2023 at 04:14:44PM -0400, Michael S. Tsirkin wrote: > Date: Thu, 22 Jun 2023 16:14:44 -0400 > From: "Michael S. Tsirkin" <mst@redhat.com> > Subject: Re: [PATCH v2 00/17] Support smp.clusters for x86 > > On Mon, May 29, 2023 at 08:30:44PM +0800, Zhao Liu wrote: > > From: Zhao Liu <zhao1.liu@intel.com> > > > > Hi list, > > > > This is the our v2 patch series, rebased on the master branch at the > > commit ac84b57b4d74 ("Merge tag 'for-upstream' of > > https://gitlab.com/bonzini/qemu into staging"). > > > > Comparing with v1 [1], v2 mainly reorganizes patches and does some > > cleanup. > > > > This series add the cluster support for x86 PC machine, which allows > > x86 can use smp.clusters to configure the modlue level CPU topology > > of x86. > > > > And since the compatibility issue (see section: ## Why not share L2 > > cache in cluster directly), this series also introduce a new command > > to adjust the topology of the x86 L2 cache. > > > > Welcome your comments! > > PC things: > > Acked-by: Michael S. Tsirkin <mst@redhat.com> > Thanks Michael! Could I double check if I can add your ACK tag to the following patches? [PATCH v2 01/17] i386: Fix comment style in topology.h [PATCH v2 02/17] tests: Rename test-x86-cpuid.c to test-x86-topo.c [PATCH v2 07/17] i386: Introduce module-level cpu topology to CPUX86State [PATCH v2 08/17] i386: Support modules_per_die in X86CPUTopoInfo [PATCH v2 09/17] i386: Support module_id in X86CPUTopoIDs [PATCH v2 10/17] i386/cpu: Introduce cluster-id to X86CPU [PATCH v2 11/17] tests: Add test case of APIC ID for module level parsing [PATCH v2 12/17] hw/i386/pc: Support smp.clusters for x86 PC machine Zhao > > > > > > # Backgroud > > > > The "clusters" parameter in "smp" is introduced by ARM [2], but x86 > > hasn't supported it. > > > > At present, x86 defaults L2 cache is shared in one core, but this is > > not enough. There're some platforms that multiple cores share the > > same L2 cache, e.g., Alder Lake-P shares L2 cache for one module of > > Atom cores [3], that is, every four Atom cores shares one L2 cache. > > Therefore, we need the new CPU topology level (cluster/module). > > > > Another reason is for hybrid architecture. cluster support not only > > provides another level of topology definition in x86, but would aslo > > provide required code change for future our hybrid topology support. > > > > > > # Overview > > > > ## Introduction of module level for x86 > > > > "cluster" in smp is the CPU topology level which is between "core" and > > die. > > > > For x86, the "cluster" in smp is corresponding to the module level [4], > > which is above the core level. So use the "module" other than "cluster" > > in x86 code. > > > > And please note that x86 already has a cpu topology level also named > > "cluster" [4], this level is at the upper level of the package. Here, > > the cluster in x86 cpu topology is completely different from the > > "clusters" as the smp parameter. After the module level is introduced, > > the cluster as the smp parameter will actually refer to the module level > > of x86. > > > > > > ## Why not share L2 cache in cluster directly > > > > Though "clusters" was introduced to help define L2 cache topology > > [2], using cluster to define x86's L2 cache topology will cause the > > compatibility problem: > > > > Currently, x86 defaults that the L2 cache is shared in one core, which > > actually implies a default setting "cores per L2 cache is 1" and > > therefore implicitly defaults to having as many L2 caches as cores. > > > > For example (i386 PC machine): > > -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) > > > > Considering the topology of the L2 cache, this (*) implicitly means "1 > > core per L2 cache" and "2 L2 caches per die". > > > > If we use cluster to configure L2 cache topology with the new default > > setting "clusters per L2 cache is 1", the above semantics will change > > to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 > > cores per L2 cache". > > > > So the same command (*) will cause changes in the L2 cache topology, > > further affecting the performance of the virtual machine. > > > > Therefore, x86 should only treat cluster as a cpu topology level and > > avoid using it to change L2 cache by default for compatibility. > > > > > > ## module level in CPUID > > > > Currently, we don't expose module level in CPUID.1FH because currently > > linux (v6.2-rc6) doesn't support module level. And exposing module and > > die levels at the same time in CPUID.1FH will cause linux to calculate > > wrong die_id. The module level should be exposed until the real machine > > has the module level in CPUID.1FH. > > > > We can configure CPUID.04H.02H (L2 cache topology) with module level by > > a new command: > > > > "-cpu,x-l2-cache-topo=cluster" > > > > More information about this command, please see the section: "## New > > property: x-l2-cache-topo". > > > > > > ## New cache topology info in CPUCacheInfo > > > > Currently, by default, the cache topology is encoded as: > > 1. i/d cache is shared in one core. > > 2. L2 cache is shared in one core. > > 3. L3 cache is shared in one die. > > > > This default general setting has caused a misunderstanding, that is, the > > cache topology is completely equated with a specific cpu topology, such > > as the connection between L2 cache and core level, and the connection > > between L3 cache and die level. > > > > In fact, the settings of these topologies depend on the specific > > platform and are not static. For example, on Alder Lake-P, every > > four Atom cores share the same L2 cache [2]. > > > > Thus, in this patch set, we explicitly define the corresponding cache > > topology for different cpu models and this has two benefits: > > 1. Easy to expand to new CPU models in the future, which has different > > cache topology. > > 2. It can easily support custom cache topology by some command (e.g., > > x-l2-cache-topo). > > > > > > ## New property: x-l2-cache-topo > > > > The property l2-cache-topo will be used to change the L2 cache topology > > in CPUID.04H. > > > > Now it allows user to set the L2 cache is shared in core level or > > cluster level. > > > > If user passes "-cpu x-l2-cache-topo=[core|cluster]" then older L2 cache > > topology will be overrided by the new topology setting. > > > > Since CPUID.04H is used by intel cpus, this property is available on > > intel cpus as for now. > > > > When necessary, it can be extended to CPUID[0x8000001D] for amd cpus. > > > > > > # Patch description > > > > patch 1-2 Cleanups about coding style and test name. > > > > patch 3-4,15 Fixes about x86 topology, intel l1 cache topology and amd > > cache topology encoding. > > > > patch 5-6 Cleanups about topology related CPUID encoding and QEMU > > topology variables. > > > > patch 7-12 Add the module as the new CPU topology level in x86, and it > > is corresponding to the cluster level in generic code. > > > > patch 13,14,16 Add cache topology infomation in cache models. > > > > patch 17 Introduce a new command to configure L2 cache topology. > > > > > > [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg03184.html > > [2]: https://patchew.org/QEMU/20211228092221.21068-1-wangyanan55@huawei.com/ > > [3]: https://www.intel.com/content/www/us/en/products/platforms/details/alder-lake-p.html > > [4]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. > > > > Best Regards, > > Zhao > > > > --- > > Changelog: > > > > Changes since v1: > > * Reordered patches. (Yanan) > > * Deprecated the patch to fix comment of machine_parse_smp_config(). > > (Yanan) > > * Rename test-x86-cpuid.c to test-x86-topo.c. (Yanan) > > * Split the intel's l1 cache topology fix into a new separate patch. > > (Yanan) > > * Combined module_id and APIC ID for module level support into one > > patch. (Yanan) > > * Make cache_into_passthrough case of cpuid 0x04 leaf in > > * cpu_x86_cpuid() use max_processor_ids_for_cache() and > > max_core_ids_in_package() to encode CPUID[4]. (Yanan) > > * Add the prefix "CPU_TOPO_LEVEL_*" for CPU topology level names. > > (Yanan) > > * Rename the "INVALID" level to "CPU_TOPO_LEVEL_UNKNOW". (Yanan) > > > > --- > > Zhao Liu (10): > > i386: Fix comment style in topology.h > > tests: Rename test-x86-cpuid.c to test-x86-topo.c > > i386/cpu: Fix i/d-cache topology to core level for Intel CPU > > i386/cpu: Use APIC ID offset to encode cache topo in CPUID[4] > > i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() > > i386: Add cache topology info in CPUCacheInfo > > i386: Use CPUCacheInfo.share_level to encode CPUID[4] > > i386: Fix NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14] > > i386: Use CPUCacheInfo.share_level to encode > > CPUID[0x8000001D].EAX[bits 25:14] > > i386: Add new property to control L2 cache topo in CPUID.04H > > > > Zhuocheng Ding (7): > > softmmu: Fix CPUSTATE.nr_cores' calculation > > i386: Introduce module-level cpu topology to CPUX86State > > i386: Support modules_per_die in X86CPUTopoInfo > > i386: Support module_id in X86CPUTopoIDs > > i386/cpu: Introduce cluster-id to X86CPU > > tests: Add test case of APIC ID for module level parsing > > hw/i386/pc: Support smp.clusters for x86 PC machine > > > > MAINTAINERS | 2 +- > > hw/i386/pc.c | 1 + > > hw/i386/x86.c | 49 +++++- > > include/hw/core/cpu.h | 2 +- > > include/hw/i386/topology.h | 68 +++++--- > > qemu-options.hx | 10 +- > > softmmu/cpus.c | 2 +- > > target/i386/cpu.c | 158 ++++++++++++++---- > > target/i386/cpu.h | 25 +++ > > tests/unit/meson.build | 4 +- > > .../{test-x86-cpuid.c => test-x86-topo.c} | 58 ++++--- > > 11 files changed, 280 insertions(+), 99 deletions(-) > > rename tests/unit/{test-x86-cpuid.c => test-x86-topo.c} (73%) > > > > -- > > 2.34.1 >
On Wed, Jun 28, 2023 at 09:18:06AM +0800, Zhao Liu wrote: > On Thu, Jun 22, 2023 at 04:14:44PM -0400, Michael S. Tsirkin wrote: > > Date: Thu, 22 Jun 2023 16:14:44 -0400 > > From: "Michael S. Tsirkin" <mst@redhat.com> > > Subject: Re: [PATCH v2 00/17] Support smp.clusters for x86 > > > > On Mon, May 29, 2023 at 08:30:44PM +0800, Zhao Liu wrote: > > > From: Zhao Liu <zhao1.liu@intel.com> > > > > > > Hi list, > > > > > > This is the our v2 patch series, rebased on the master branch at the > > > commit ac84b57b4d74 ("Merge tag 'for-upstream' of > > > https://gitlab.com/bonzini/qemu into staging"). > > > > > > Comparing with v1 [1], v2 mainly reorganizes patches and does some > > > cleanup. > > > > > > This series add the cluster support for x86 PC machine, which allows > > > x86 can use smp.clusters to configure the modlue level CPU topology > > > of x86. > > > > > > And since the compatibility issue (see section: ## Why not share L2 > > > cache in cluster directly), this series also introduce a new command > > > to adjust the topology of the x86 L2 cache. > > > > > > Welcome your comments! > > > > PC things: > > > > Acked-by: Michael S. Tsirkin <mst@redhat.com> > > > > Thanks Michael! > > Could I double check if I can add your ACK tag to the following patches? > > [PATCH v2 01/17] i386: Fix comment style in topology.h > [PATCH v2 02/17] tests: Rename test-x86-cpuid.c to test-x86-topo.c > [PATCH v2 07/17] i386: Introduce module-level cpu topology to > CPUX86State > [PATCH v2 08/17] i386: Support modules_per_die in X86CPUTopoInfo > [PATCH v2 09/17] i386: Support module_id in X86CPUTopoIDs > [PATCH v2 10/17] i386/cpu: Introduce cluster-id to X86CPU > [PATCH v2 11/17] tests: Add test case of APIC ID for module level parsing > [PATCH v2 12/17] hw/i386/pc: Support smp.clusters for x86 PC machine > > Zhao Sure > > > > > > > > > > # Backgroud > > > > > > The "clusters" parameter in "smp" is introduced by ARM [2], but x86 > > > hasn't supported it. > > > > > > At present, x86 defaults L2 cache is shared in one core, but this is > > > not enough. There're some platforms that multiple cores share the > > > same L2 cache, e.g., Alder Lake-P shares L2 cache for one module of > > > Atom cores [3], that is, every four Atom cores shares one L2 cache. > > > Therefore, we need the new CPU topology level (cluster/module). > > > > > > Another reason is for hybrid architecture. cluster support not only > > > provides another level of topology definition in x86, but would aslo > > > provide required code change for future our hybrid topology support. > > > > > > > > > # Overview > > > > > > ## Introduction of module level for x86 > > > > > > "cluster" in smp is the CPU topology level which is between "core" and > > > die. > > > > > > For x86, the "cluster" in smp is corresponding to the module level [4], > > > which is above the core level. So use the "module" other than "cluster" > > > in x86 code. > > > > > > And please note that x86 already has a cpu topology level also named > > > "cluster" [4], this level is at the upper level of the package. Here, > > > the cluster in x86 cpu topology is completely different from the > > > "clusters" as the smp parameter. After the module level is introduced, > > > the cluster as the smp parameter will actually refer to the module level > > > of x86. > > > > > > > > > ## Why not share L2 cache in cluster directly > > > > > > Though "clusters" was introduced to help define L2 cache topology > > > [2], using cluster to define x86's L2 cache topology will cause the > > > compatibility problem: > > > > > > Currently, x86 defaults that the L2 cache is shared in one core, which > > > actually implies a default setting "cores per L2 cache is 1" and > > > therefore implicitly defaults to having as many L2 caches as cores. > > > > > > For example (i386 PC machine): > > > -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) > > > > > > Considering the topology of the L2 cache, this (*) implicitly means "1 > > > core per L2 cache" and "2 L2 caches per die". > > > > > > If we use cluster to configure L2 cache topology with the new default > > > setting "clusters per L2 cache is 1", the above semantics will change > > > to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 > > > cores per L2 cache". > > > > > > So the same command (*) will cause changes in the L2 cache topology, > > > further affecting the performance of the virtual machine. > > > > > > Therefore, x86 should only treat cluster as a cpu topology level and > > > avoid using it to change L2 cache by default for compatibility. > > > > > > > > > ## module level in CPUID > > > > > > Currently, we don't expose module level in CPUID.1FH because currently > > > linux (v6.2-rc6) doesn't support module level. And exposing module and > > > die levels at the same time in CPUID.1FH will cause linux to calculate > > > wrong die_id. The module level should be exposed until the real machine > > > has the module level in CPUID.1FH. > > > > > > We can configure CPUID.04H.02H (L2 cache topology) with module level by > > > a new command: > > > > > > "-cpu,x-l2-cache-topo=cluster" > > > > > > More information about this command, please see the section: "## New > > > property: x-l2-cache-topo". > > > > > > > > > ## New cache topology info in CPUCacheInfo > > > > > > Currently, by default, the cache topology is encoded as: > > > 1. i/d cache is shared in one core. > > > 2. L2 cache is shared in one core. > > > 3. L3 cache is shared in one die. > > > > > > This default general setting has caused a misunderstanding, that is, the > > > cache topology is completely equated with a specific cpu topology, such > > > as the connection between L2 cache and core level, and the connection > > > between L3 cache and die level. > > > > > > In fact, the settings of these topologies depend on the specific > > > platform and are not static. For example, on Alder Lake-P, every > > > four Atom cores share the same L2 cache [2]. > > > > > > Thus, in this patch set, we explicitly define the corresponding cache > > > topology for different cpu models and this has two benefits: > > > 1. Easy to expand to new CPU models in the future, which has different > > > cache topology. > > > 2. It can easily support custom cache topology by some command (e.g., > > > x-l2-cache-topo). > > > > > > > > > ## New property: x-l2-cache-topo > > > > > > The property l2-cache-topo will be used to change the L2 cache topology > > > in CPUID.04H. > > > > > > Now it allows user to set the L2 cache is shared in core level or > > > cluster level. > > > > > > If user passes "-cpu x-l2-cache-topo=[core|cluster]" then older L2 cache > > > topology will be overrided by the new topology setting. > > > > > > Since CPUID.04H is used by intel cpus, this property is available on > > > intel cpus as for now. > > > > > > When necessary, it can be extended to CPUID[0x8000001D] for amd cpus. > > > > > > > > > # Patch description > > > > > > patch 1-2 Cleanups about coding style and test name. > > > > > > patch 3-4,15 Fixes about x86 topology, intel l1 cache topology and amd > > > cache topology encoding. > > > > > > patch 5-6 Cleanups about topology related CPUID encoding and QEMU > > > topology variables. > > > > > > patch 7-12 Add the module as the new CPU topology level in x86, and it > > > is corresponding to the cluster level in generic code. > > > > > > patch 13,14,16 Add cache topology infomation in cache models. > > > > > > patch 17 Introduce a new command to configure L2 cache topology. > > > > > > > > > [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg03184.html > > > [2]: https://patchew.org/QEMU/20211228092221.21068-1-wangyanan55@huawei.com/ > > > [3]: https://www.intel.com/content/www/us/en/products/platforms/details/alder-lake-p.html > > > [4]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. > > > > > > Best Regards, > > > Zhao > > > > > > --- > > > Changelog: > > > > > > Changes since v1: > > > * Reordered patches. (Yanan) > > > * Deprecated the patch to fix comment of machine_parse_smp_config(). > > > (Yanan) > > > * Rename test-x86-cpuid.c to test-x86-topo.c. (Yanan) > > > * Split the intel's l1 cache topology fix into a new separate patch. > > > (Yanan) > > > * Combined module_id and APIC ID for module level support into one > > > patch. (Yanan) > > > * Make cache_into_passthrough case of cpuid 0x04 leaf in > > > * cpu_x86_cpuid() use max_processor_ids_for_cache() and > > > max_core_ids_in_package() to encode CPUID[4]. (Yanan) > > > * Add the prefix "CPU_TOPO_LEVEL_*" for CPU topology level names. > > > (Yanan) > > > * Rename the "INVALID" level to "CPU_TOPO_LEVEL_UNKNOW". (Yanan) > > > > > > --- > > > Zhao Liu (10): > > > i386: Fix comment style in topology.h > > > tests: Rename test-x86-cpuid.c to test-x86-topo.c > > > i386/cpu: Fix i/d-cache topology to core level for Intel CPU > > > i386/cpu: Use APIC ID offset to encode cache topo in CPUID[4] > > > i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() > > > i386: Add cache topology info in CPUCacheInfo > > > i386: Use CPUCacheInfo.share_level to encode CPUID[4] > > > i386: Fix NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14] > > > i386: Use CPUCacheInfo.share_level to encode > > > CPUID[0x8000001D].EAX[bits 25:14] > > > i386: Add new property to control L2 cache topo in CPUID.04H > > > > > > Zhuocheng Ding (7): > > > softmmu: Fix CPUSTATE.nr_cores' calculation > > > i386: Introduce module-level cpu topology to CPUX86State > > > i386: Support modules_per_die in X86CPUTopoInfo > > > i386: Support module_id in X86CPUTopoIDs > > > i386/cpu: Introduce cluster-id to X86CPU > > > tests: Add test case of APIC ID for module level parsing > > > hw/i386/pc: Support smp.clusters for x86 PC machine > > > > > > MAINTAINERS | 2 +- > > > hw/i386/pc.c | 1 + > > > hw/i386/x86.c | 49 +++++- > > > include/hw/core/cpu.h | 2 +- > > > include/hw/i386/topology.h | 68 +++++--- > > > qemu-options.hx | 10 +- > > > softmmu/cpus.c | 2 +- > > > target/i386/cpu.c | 158 ++++++++++++++---- > > > target/i386/cpu.h | 25 +++ > > > tests/unit/meson.build | 4 +- > > > .../{test-x86-cpuid.c => test-x86-topo.c} | 58 ++++--- > > > 11 files changed, 280 insertions(+), 99 deletions(-) > > > rename tests/unit/{test-x86-cpuid.c => test-x86-topo.c} (73%) > > > > > > -- > > > 2.34.1 > >
From: Zhao Liu <zhao1.liu@intel.com> Hi list, This is the our v2 patch series, rebased on the master branch at the commit ac84b57b4d74 ("Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging"). Comparing with v1 [1], v2 mainly reorganizes patches and does some cleanup. This series add the cluster support for x86 PC machine, which allows x86 can use smp.clusters to configure the modlue level CPU topology of x86. And since the compatibility issue (see section: ## Why not share L2 cache in cluster directly), this series also introduce a new command to adjust the topology of the x86 L2 cache. Welcome your comments! # Backgroud The "clusters" parameter in "smp" is introduced by ARM [2], but x86 hasn't supported it. At present, x86 defaults L2 cache is shared in one core, but this is not enough. There're some platforms that multiple cores share the same L2 cache, e.g., Alder Lake-P shares L2 cache for one module of Atom cores [3], that is, every four Atom cores shares one L2 cache. Therefore, we need the new CPU topology level (cluster/module). Another reason is for hybrid architecture. cluster support not only provides another level of topology definition in x86, but would aslo provide required code change for future our hybrid topology support. # Overview ## Introduction of module level for x86 "cluster" in smp is the CPU topology level which is between "core" and die. For x86, the "cluster" in smp is corresponding to the module level [4], which is above the core level. So use the "module" other than "cluster" in x86 code. And please note that x86 already has a cpu topology level also named "cluster" [4], this level is at the upper level of the package. Here, the cluster in x86 cpu topology is completely different from the "clusters" as the smp parameter. After the module level is introduced, the cluster as the smp parameter will actually refer to the module level of x86. ## Why not share L2 cache in cluster directly Though "clusters" was introduced to help define L2 cache topology [2], using cluster to define x86's L2 cache topology will cause the compatibility problem: Currently, x86 defaults that the L2 cache is shared in one core, which actually implies a default setting "cores per L2 cache is 1" and therefore implicitly defaults to having as many L2 caches as cores. For example (i386 PC machine): -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 (*) Considering the topology of the L2 cache, this (*) implicitly means "1 core per L2 cache" and "2 L2 caches per die". If we use cluster to configure L2 cache topology with the new default setting "clusters per L2 cache is 1", the above semantics will change to "2 cores per cluster" and "1 cluster per L2 cache", that is, "2 cores per L2 cache". So the same command (*) will cause changes in the L2 cache topology, further affecting the performance of the virtual machine. Therefore, x86 should only treat cluster as a cpu topology level and avoid using it to change L2 cache by default for compatibility. ## module level in CPUID Currently, we don't expose module level in CPUID.1FH because currently linux (v6.2-rc6) doesn't support module level. And exposing module and die levels at the same time in CPUID.1FH will cause linux to calculate wrong die_id. The module level should be exposed until the real machine has the module level in CPUID.1FH. We can configure CPUID.04H.02H (L2 cache topology) with module level by a new command: "-cpu,x-l2-cache-topo=cluster" More information about this command, please see the section: "## New property: x-l2-cache-topo". ## New cache topology info in CPUCacheInfo Currently, by default, the cache topology is encoded as: 1. i/d cache is shared in one core. 2. L2 cache is shared in one core. 3. L3 cache is shared in one die. This default general setting has caused a misunderstanding, that is, the cache topology is completely equated with a specific cpu topology, such as the connection between L2 cache and core level, and the connection between L3 cache and die level. In fact, the settings of these topologies depend on the specific platform and are not static. For example, on Alder Lake-P, every four Atom cores share the same L2 cache [2]. Thus, in this patch set, we explicitly define the corresponding cache topology for different cpu models and this has two benefits: 1. Easy to expand to new CPU models in the future, which has different cache topology. 2. It can easily support custom cache topology by some command (e.g., x-l2-cache-topo). ## New property: x-l2-cache-topo The property l2-cache-topo will be used to change the L2 cache topology in CPUID.04H. Now it allows user to set the L2 cache is shared in core level or cluster level. If user passes "-cpu x-l2-cache-topo=[core|cluster]" then older L2 cache topology will be overrided by the new topology setting. Since CPUID.04H is used by intel cpus, this property is available on intel cpus as for now. When necessary, it can be extended to CPUID[0x8000001D] for amd cpus. # Patch description patch 1-2 Cleanups about coding style and test name. patch 3-4,15 Fixes about x86 topology, intel l1 cache topology and amd cache topology encoding. patch 5-6 Cleanups about topology related CPUID encoding and QEMU topology variables. patch 7-12 Add the module as the new CPU topology level in x86, and it is corresponding to the cluster level in generic code. patch 13,14,16 Add cache topology infomation in cache models. patch 17 Introduce a new command to configure L2 cache topology. [1]: https://lists.gnu.org/archive/html/qemu-devel/2023-02/msg03184.html [2]: https://patchew.org/QEMU/20211228092221.21068-1-wangyanan55@huawei.com/ [3]: https://www.intel.com/content/www/us/en/products/platforms/details/alder-lake-p.html [4]: SDM, vol.3, ch.9, 9.9.1 Hierarchical Mapping of Shared Resources. Best Regards, Zhao --- Changelog: Changes since v1: * Reordered patches. (Yanan) * Deprecated the patch to fix comment of machine_parse_smp_config(). (Yanan) * Rename test-x86-cpuid.c to test-x86-topo.c. (Yanan) * Split the intel's l1 cache topology fix into a new separate patch. (Yanan) * Combined module_id and APIC ID for module level support into one patch. (Yanan) * Make cache_into_passthrough case of cpuid 0x04 leaf in * cpu_x86_cpuid() use max_processor_ids_for_cache() and max_core_ids_in_package() to encode CPUID[4]. (Yanan) * Add the prefix "CPU_TOPO_LEVEL_*" for CPU topology level names. (Yanan) * Rename the "INVALID" level to "CPU_TOPO_LEVEL_UNKNOW". (Yanan) --- Zhao Liu (10): i386: Fix comment style in topology.h tests: Rename test-x86-cpuid.c to test-x86-topo.c i386/cpu: Fix i/d-cache topology to core level for Intel CPU i386/cpu: Use APIC ID offset to encode cache topo in CPUID[4] i386/cpu: Consolidate the use of topo_info in cpu_x86_cpuid() i386: Add cache topology info in CPUCacheInfo i386: Use CPUCacheInfo.share_level to encode CPUID[4] i386: Fix NumSharingCache for CPUID[0x8000001D].EAX[bits 25:14] i386: Use CPUCacheInfo.share_level to encode CPUID[0x8000001D].EAX[bits 25:14] i386: Add new property to control L2 cache topo in CPUID.04H Zhuocheng Ding (7): softmmu: Fix CPUSTATE.nr_cores' calculation i386: Introduce module-level cpu topology to CPUX86State i386: Support modules_per_die in X86CPUTopoInfo i386: Support module_id in X86CPUTopoIDs i386/cpu: Introduce cluster-id to X86CPU tests: Add test case of APIC ID for module level parsing hw/i386/pc: Support smp.clusters for x86 PC machine MAINTAINERS | 2 +- hw/i386/pc.c | 1 + hw/i386/x86.c | 49 +++++- include/hw/core/cpu.h | 2 +- include/hw/i386/topology.h | 68 +++++--- qemu-options.hx | 10 +- softmmu/cpus.c | 2 +- target/i386/cpu.c | 158 ++++++++++++++---- target/i386/cpu.h | 25 +++ tests/unit/meson.build | 4 +- .../{test-x86-cpuid.c => test-x86-topo.c} | 58 ++++--- 11 files changed, 280 insertions(+), 99 deletions(-) rename tests/unit/{test-x86-cpuid.c => test-x86-topo.c} (73%)