Hi, Babu, > Newer AMD processors support the new feature Bandwidth Monitoring Event > Configuration (BMEC). > > The feature support is identified via CPUID Fn8000_0020_EBX_x0 (ECX=0). > Bits Field Name Description > 3 EVT_CFG Bandwidth Monitoring Event Configuration (BMEC) > > Currently, the bandwidth monitoring events mbm_total_bytes and > mbm_local_bytes are set to count all the total and local reads/writes > respectively. With the introduction of slow memory, the two counters are not > enough to count all the different types of memory events. With the feature > BMEC, the users have the option to configure mbm_total_bytes and > mbm_local_bytes to count the specific type of events. > > Each BMEC event has a configuration MSR, QOS_EVT_CFG (0xc000_0400h + > EventID) which contains one field for each bandwidth type that can be used to > configure the bandwidth event to track any combination of supported > bandwidth types. The event will count requests from every bandwidth type bit > that is set in the corresponding configuration register. > > Following are the types of events supported: > > ==== ======================================================== > Bits Description > ==== ======================================================== > 6 Dirty Victims from the QOS domain to all types of memory > 5 Reads to slow memory in the non-local NUMA domain > 4 Reads to slow memory in the local NUMA domain > 3 Non-temporal writes to non-local NUMA domain > 2 Non-temporal writes to local NUMA domain > 1 Reads to memory in the non-local NUMA domain > 0 Reads to memory in the local NUMA domain > ==== ======================================================== > > By default, the mbm_total_bytes configuration is set to 0x7F to count all the > event types and the mbm_local_bytes configuration is set to > 0x15 to count all the local memory events. > > Feature description is available in the specification, "AMD64 Technology > Platform Quality of Service Extensions, Revision: 1.03 Publication > > Link: https://www.amd.com/en/support/tech-docs/amd64-technology- > platform-quality-service-extensions > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > --- > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/kernel/cpu/cpuid-deps.c | 1 + > arch/x86/kernel/cpu/scattered.c | 1 + > 3 files changed, 3 insertions(+) > > diff --git a/arch/x86/include/asm/cpufeatures.h > b/arch/x86/include/asm/cpufeatures.h > index d68b4c9c181d..6732ca0117be 100644 > --- a/arch/x86/include/asm/cpufeatures.h > +++ b/arch/x86/include/asm/cpufeatures.h > @@ -306,6 +306,7 @@ > #define X86_FEATURE_RSB_VMEXIT_LITE (11*32+17) /* "" Fill RSB on VM > exit when EIBRS is enabled */ > #define X86_FEATURE_CALL_DEPTH (11*32+18) /* "" Call depth > tracking for RSB stuffing */ > #define X86_FEATURE_SMBA (11*32+19) /* Slow Memory > Bandwidth Allocation */ > +#define X86_FEATURE_BMEC (11*32+20) /* AMD Bandwidth > Monitoring Event Configuration (BMEC) */ > > /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */ > #define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI > instructions */ > diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid- > deps.c > index c881bcafba7d..4555f9596ccf 100644 > --- a/arch/x86/kernel/cpu/cpuid-deps.c > +++ b/arch/x86/kernel/cpu/cpuid-deps.c > @@ -68,6 +68,7 @@ static const struct cpuid_dep cpuid_deps[] = { > { X86_FEATURE_CQM_OCCUP_LLC, > X86_FEATURE_CQM_LLC }, > { X86_FEATURE_CQM_MBM_TOTAL, > X86_FEATURE_CQM_LLC }, > { X86_FEATURE_CQM_MBM_LOCAL, > X86_FEATURE_CQM_LLC }, > + { X86_FEATURE_BMEC, X86_FEATURE_CQM_LLC }, Shouldn't X86_FEATURE_BMEC really depend on X86_FEATURE_CQM_MBM_LOCAL and _TOTAL? CQM_MBM_LOCAL and/or _TOTAL can be disabled but CQM_LLC can still be enabled. In this case, BMEC shouldn't be enabled, right? But with this patch, BMEC will be enabled but it won't work well as CQM_MBM_TOTAL/_LOCAL are not enabled. You may remove the above line and add these two lines: + { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_TOTAL }, + { X86_FEATURE_BMEC, X86_FEATURE_CQM_MBM_LOCAL }, Thanks. -Fenghua
