Messages in this thread | | | Subject | Re: [PATCH V2 1/5] powerpc/perf: Expose processor pipeline stage cycles using PERF_SAMPLE_WEIGHT_STRUCT | From | Madhavan Srinivasan <> | Date | Fri, 26 Mar 2021 14:02:02 +0530 |
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On 3/25/21 6:36 PM, Arnaldo Carvalho de Melo wrote: > Em Wed, Mar 24, 2021 at 10:05:23AM +0530, Madhavan Srinivasan escreveu: >> On 3/22/21 8:27 PM, Athira Rajeev wrote: >>> Performance Monitoring Unit (PMU) registers in powerpc provides >>> information on cycles elapsed between different stages in the >>> pipeline. This can be used for application tuning. On ISA v3.1 >>> platform, this information is exposed by sampling registers. >>> Patch adds kernel support to capture two of the cycle counters >>> as part of perf sample using the sample type: >>> PERF_SAMPLE_WEIGHT_STRUCT. >>> >>> The power PMU function 'get_mem_weight' currently uses 64 bit weight >>> field of perf_sample_data to capture memory latency. But following the >>> introduction of PERF_SAMPLE_WEIGHT_TYPE, weight field could contain >>> 64-bit or 32-bit value depending on the architexture support for >>> PERF_SAMPLE_WEIGHT_STRUCT. Patches uses WEIGHT_STRUCT to expose the >>> pipeline stage cycles info. Hence update the ppmu functions to work for >>> 64-bit and 32-bit weight values. >>> >>> If the sample type is PERF_SAMPLE_WEIGHT, use the 64-bit weight field. >>> if the sample type is PERF_SAMPLE_WEIGHT_STRUCT, memory subsystem >>> latency is stored in the low 32bits of perf_sample_weight structure. >>> Also for CPU_FTR_ARCH_31, capture the two cycle counter information in >>> two 16 bit fields of perf_sample_weight structure. >> Changes looks fine to me. > You mean just the kernel part or can I add your Reviewed-by to all the > patchset?
Yes, kindly add it, I did review the patchset. My bad, i should have mentioned it here
or should have replied to the cover letter.
Maddy
> >> Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com> >> >> >>> Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com> >>> --- >>> arch/powerpc/include/asm/perf_event_server.h | 2 +- >>> arch/powerpc/perf/core-book3s.c | 4 ++-- >>> arch/powerpc/perf/isa207-common.c | 29 +++++++++++++++++++++++++--- >>> arch/powerpc/perf/isa207-common.h | 6 +++++- >>> 4 files changed, 34 insertions(+), 7 deletions(-) >>> >>> diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h >>> index 00e7e671bb4b..112cf092d7b3 100644 >>> --- a/arch/powerpc/include/asm/perf_event_server.h >>> +++ b/arch/powerpc/include/asm/perf_event_server.h >>> @@ -43,7 +43,7 @@ struct power_pmu { >>> u64 alt[]); >>> void (*get_mem_data_src)(union perf_mem_data_src *dsrc, >>> u32 flags, struct pt_regs *regs); >>> - void (*get_mem_weight)(u64 *weight); >>> + void (*get_mem_weight)(u64 *weight, u64 type); >>> unsigned long group_constraint_mask; >>> unsigned long group_constraint_val; >>> u64 (*bhrb_filter_map)(u64 branch_sample_type); >>> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c >>> index 766f064f00fb..6936763246bd 100644 >>> --- a/arch/powerpc/perf/core-book3s.c >>> +++ b/arch/powerpc/perf/core-book3s.c >>> @@ -2206,9 +2206,9 @@ static void record_and_restart(struct perf_event *event, unsigned long val, >>> ppmu->get_mem_data_src) >>> ppmu->get_mem_data_src(&data.data_src, ppmu->flags, regs); >>> - if (event->attr.sample_type & PERF_SAMPLE_WEIGHT && >>> + if (event->attr.sample_type & PERF_SAMPLE_WEIGHT_TYPE && >>> ppmu->get_mem_weight) >>> - ppmu->get_mem_weight(&data.weight.full); >>> + ppmu->get_mem_weight(&data.weight.full, event->attr.sample_type); >>> if (perf_event_overflow(event, &data, regs)) >>> power_pmu_stop(event, 0); >>> diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c >>> index e4f577da33d8..5dcbdbd54598 100644 >>> --- a/arch/powerpc/perf/isa207-common.c >>> +++ b/arch/powerpc/perf/isa207-common.c >>> @@ -284,8 +284,10 @@ void isa207_get_mem_data_src(union perf_mem_data_src *dsrc, u32 flags, >>> } >>> } >>> -void isa207_get_mem_weight(u64 *weight) >>> +void isa207_get_mem_weight(u64 *weight, u64 type) >>> { >>> + union perf_sample_weight *weight_fields; >>> + u64 weight_lat; >>> u64 mmcra = mfspr(SPRN_MMCRA); >>> u64 exp = MMCRA_THR_CTR_EXP(mmcra); >>> u64 mantissa = MMCRA_THR_CTR_MANT(mmcra); >>> @@ -296,9 +298,30 @@ void isa207_get_mem_weight(u64 *weight) >>> mantissa = P10_MMCRA_THR_CTR_MANT(mmcra); >>> if (val == 0 || val == 7) >>> - *weight = 0; >>> + weight_lat = 0; >>> else >>> - *weight = mantissa << (2 * exp); >>> + weight_lat = mantissa << (2 * exp); >>> + >>> + /* >>> + * Use 64 bit weight field (full) if sample type is >>> + * WEIGHT. >>> + * >>> + * if sample type is WEIGHT_STRUCT: >>> + * - store memory latency in the lower 32 bits. >>> + * - For ISA v3.1, use remaining two 16 bit fields of >>> + * perf_sample_weight to store cycle counter values >>> + * from sier2. >>> + */ >>> + weight_fields = (union perf_sample_weight *)weight; >>> + if (type & PERF_SAMPLE_WEIGHT) >>> + weight_fields->full = weight_lat; >>> + else { >>> + weight_fields->var1_dw = (u32)weight_lat; >>> + if (cpu_has_feature(CPU_FTR_ARCH_31)) { >>> + weight_fields->var2_w = P10_SIER2_FINISH_CYC(mfspr(SPRN_SIER2)); >>> + weight_fields->var3_w = P10_SIER2_DISPATCH_CYC(mfspr(SPRN_SIER2)); >>> + } >>> + } >>> } >>> int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, u64 event_config1) >>> diff --git a/arch/powerpc/perf/isa207-common.h b/arch/powerpc/perf/isa207-common.h >>> index 1af0e8c97ac7..fc30d43c4d0c 100644 >>> --- a/arch/powerpc/perf/isa207-common.h >>> +++ b/arch/powerpc/perf/isa207-common.h >>> @@ -265,6 +265,10 @@ >>> #define ISA207_SIER_DATA_SRC_SHIFT 53 >>> #define ISA207_SIER_DATA_SRC_MASK (0x7ull << ISA207_SIER_DATA_SRC_SHIFT) >>> +/* Bits in SIER2/SIER3 for Power10 */ >>> +#define P10_SIER2_FINISH_CYC(sier2) (((sier2) >> (63 - 37)) & 0x7fful) >>> +#define P10_SIER2_DISPATCH_CYC(sier2) (((sier2) >> (63 - 13)) & 0x7fful) >>> + >>> #define P(a, b) PERF_MEM_S(a, b) >>> #define PH(a, b) (P(LVL, HIT) | P(a, b)) >>> #define PM(a, b) (P(LVL, MISS) | P(a, b)) >>> @@ -278,6 +282,6 @@ int isa207_get_alternatives(u64 event, u64 alt[], int size, unsigned int flags, >>> const unsigned int ev_alt[][MAX_ALT]); >>> void isa207_get_mem_data_src(union perf_mem_data_src *dsrc, u32 flags, >>> struct pt_regs *regs); >>> -void isa207_get_mem_weight(u64 *weight); >>> +void isa207_get_mem_weight(u64 *weight, u64 type); >>> #endif
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