[PATCH v2 09/10] tools/perf: Add perf tools support for extended register capability in powerpc
Athira Rajeev
atrajeev at linux.vnet.ibm.com
Thu Jul 9 13:10:22 AEST 2020
> On 08-Jul-2020, at 5:34 PM, Michael Ellerman <mpe at ellerman.id.au> wrote:
>
> Athira Rajeev <atrajeev at linux.vnet.ibm.com <mailto:atrajeev at linux.vnet.ibm.com>> writes:
>> From: Anju T Sudhakar <anju at linux.vnet.ibm.com>
>>
>> Add extended regs to sample_reg_mask in the tool side to use
>> with `-I?` option. Perf tools side uses extended mask to display
>> the platform supported register names (with -I? option) to the user
>> and also send this mask to the kernel to capture the extended registers
>> in each sample. Hence decide the mask value based on the processor
>> version.
>>
>> Signed-off-by: Anju T Sudhakar <anju at linux.vnet.ibm.com>
>> [Decide extended mask at run time based on platform]
>> Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
>> Reviewed-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
>
> Will need an ack from perf tools folks, who are not on Cc by the looks.
>
Yes, my bad. Will make sure to add proper Cc
>> diff --git a/tools/arch/powerpc/include/uapi/asm/perf_regs.h b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> index f599064..485b1d5 100644
>> --- a/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> +++ b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> @@ -48,6 +48,18 @@ enum perf_event_powerpc_regs {
>> PERF_REG_POWERPC_DSISR,
>> PERF_REG_POWERPC_SIER,
>> PERF_REG_POWERPC_MMCRA,
>> - PERF_REG_POWERPC_MAX,
>> + /* Extended registers */
>> + PERF_REG_POWERPC_MMCR0,
>> + PERF_REG_POWERPC_MMCR1,
>> + PERF_REG_POWERPC_MMCR2,
>> + /* Max regs without the extended regs */
>> + PERF_REG_POWERPC_MAX = PERF_REG_POWERPC_MMCRA + 1,
>
> I don't really understand this idea of a max that's not the max.
>
>> };
>> +
>> +#define PERF_REG_PMU_MASK ((1ULL << PERF_REG_POWERPC_MAX) - 1)
>> +
>> +/* PERF_REG_EXTENDED_MASK value for CPU_FTR_ARCH_300 */
>> +#define PERF_REG_PMU_MASK_300 (((1ULL << (PERF_REG_POWERPC_MMCR2 + 1)) - 1) \
>> + - PERF_REG_PMU_MASK)
>> +
>> #endif /* _UAPI_ASM_POWERPC_PERF_REGS_H */
>> diff --git a/tools/perf/arch/powerpc/include/perf_regs.h b/tools/perf/arch/powerpc/include/perf_regs.h
>> index e18a355..46ed00d 100644
>> --- a/tools/perf/arch/powerpc/include/perf_regs.h
>> +++ b/tools/perf/arch/powerpc/include/perf_regs.h
>> @@ -64,7 +64,10 @@
>> [PERF_REG_POWERPC_DAR] = "dar",
>> [PERF_REG_POWERPC_DSISR] = "dsisr",
>> [PERF_REG_POWERPC_SIER] = "sier",
>> - [PERF_REG_POWERPC_MMCRA] = "mmcra"
>> + [PERF_REG_POWERPC_MMCRA] = "mmcra",
>> + [PERF_REG_POWERPC_MMCR0] = "mmcr0",
>> + [PERF_REG_POWERPC_MMCR1] = "mmcr1",
>> + [PERF_REG_POWERPC_MMCR2] = "mmcr2",
>> };
>>
>> static inline const char *perf_reg_name(int id)
>> diff --git a/tools/perf/arch/powerpc/util/perf_regs.c b/tools/perf/arch/powerpc/util/perf_regs.c
>> index 0a52429..9179230 100644
>> --- a/tools/perf/arch/powerpc/util/perf_regs.c
>> +++ b/tools/perf/arch/powerpc/util/perf_regs.c
>> @@ -6,9 +6,14 @@
>>
>> #include "../../../util/perf_regs.h"
>> #include "../../../util/debug.h"
>> +#include "../../../util/event.h"
>> +#include "../../../util/header.h"
>> +#include "../../../perf-sys.h"
>>
>> #include <linux/kernel.h>
>>
>> +#define PVR_POWER9 0x004E
>> +
>> const struct sample_reg sample_reg_masks[] = {
>> SMPL_REG(r0, PERF_REG_POWERPC_R0),
>> SMPL_REG(r1, PERF_REG_POWERPC_R1),
>> @@ -55,6 +60,9 @@
>> SMPL_REG(dsisr, PERF_REG_POWERPC_DSISR),
>> SMPL_REG(sier, PERF_REG_POWERPC_SIER),
>> SMPL_REG(mmcra, PERF_REG_POWERPC_MMCRA),
>> + SMPL_REG(mmcr0, PERF_REG_POWERPC_MMCR0),
>> + SMPL_REG(mmcr1, PERF_REG_POWERPC_MMCR1),
>> + SMPL_REG(mmcr2, PERF_REG_POWERPC_MMCR2),
>> SMPL_REG_END
>> };
>>
>> @@ -163,3 +171,50 @@ int arch_sdt_arg_parse_op(char *old_op, char **new_op)
>>
>> return SDT_ARG_VALID;
>> }
>> +
>> +uint64_t arch__intr_reg_mask(void)
>> +{
>> + struct perf_event_attr attr = {
>> + .type = PERF_TYPE_HARDWARE,
>> + .config = PERF_COUNT_HW_CPU_CYCLES,
>> + .sample_type = PERF_SAMPLE_REGS_INTR,
>> + .precise_ip = 1,
>> + .disabled = 1,
>> + .exclude_kernel = 1,
>> + };
>> + int fd, ret;
>> + char buffer[64];
>> + u32 version;
>> + u64 extended_mask = 0;
>> +
>> + /* Get the PVR value to set the extended
>> + * mask specific to platform
>
> Comment format is wrong, and punctuation please.
>
>> + */
>> + get_cpuid(buffer, sizeof(buffer));
>> + ret = sscanf(buffer, "%u,", &version);
>
> This is powerpc specific code, why not just use mfspr(SPRN_PVR), rather
> than redirecting via printf/sscanf.
Hi Michael
For perf tools, defines for `mfspr` , `SPRN_PVR` are in arch/powerpc/util/header.c
So I have re-used existing utility. Otherwise, we will need to include these defines here as well
Does that sounds good ?
>
>> +
>> + if (ret != 1) {
>> + pr_debug("Failed to get the processor version, unable to output extended registers\n");
>> + return PERF_REGS_MASK;
>> + }
>> +
>> + if (version == PVR_POWER9)
>> + extended_mask = PERF_REG_PMU_MASK_300;
>> + else
>> + return PERF_REGS_MASK;
>> +
>> + attr.sample_regs_intr = extended_mask;
>> + attr.sample_period = 1;
>> + event_attr_init(&attr);
>> +
>> + /*
>> + * check if the pmu supports perf extended regs, before
>> + * returning the register mask to sample.
>> + */
>> + fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
>> + if (fd != -1) {
>> + close(fd);
>> + return (extended_mask | PERF_REGS_MASK);
>> + }
>> + return PERF_REGS_MASK;
>
> I think this would read a bit better like:
>
> mask = PERF_REGS_MASK;
>
> if (version == PVR_POWER9)
> extended_mask = PERF_REG_PMU_MASK_300;
> else
> return mask;
>
> attr.sample_regs_intr = extended_mask;
> attr.sample_period = 1;
> event_attr_init(&attr);
>
> /*
> * check if the pmu supports perf extended regs, before
> * returning the register mask to sample.
> */
> fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
> if (fd != -1) {
> close(fd);
> mask |= extended_mask;
> }
>
> return mask;
Sure, I will try with this change
Thanks
Athira
>
>
> cheers
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