[PATCH V4 2/2] tools/perf: Add perf tools support for extended register capability in powerpc

Nageswara R Sastry nasastry at in.ibm.com
Thu May 28 19:37:00 AEST 2020


"Athira Rajeev" <atrajeev at linux.vnet.ibm.com> wrote on 27/05/2020 03:20:18
PM:

> From: "Athira Rajeev" <atrajeev at linux.vnet.ibm.com>
> To: linuxppc-dev at lists.ozlabs.org
> Cc: linux-kernel at vger.kernel.org, ravi.bangoria at linux.ibm.com,
> maddy at linux.vnet.ibm.com, acme at kernel.org, anju at linux.vnet.ibm.com,
> jolsa at kernel.org, mpe at ellerman.id.au, atrajeev at linux.vnet.ibm.com
> Date: 28/05/2020 02:46 PM
> Subject: [PATCH V4 2/2] tools/perf: Add perf tools support for
> extended register capability in powerpc
>
> 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>

Tested-by: Nageswara R Sastry <nasastry at in.ibm.com>
Tested with 5.7.0-rc2
Tested the following scenarios
1. perf record -I
2. perf report -D  # in output check for the registers
3. perf record -I<register name>
4. perf record -I<non existing register name>
5. perf record -I<non existing register name with special characters>
6. perf record -I<register name> -e <different event names>

> ---
>  tools/arch/powerpc/include/uapi/asm/perf_regs.h | 14 ++++++-
>  tools/perf/arch/powerpc/include/perf_regs.h     |  5 ++-
>  tools/perf/arch/powerpc/util/perf_regs.c        | 55 ++++++++++++++
> +++++++++++
>  3 files changed, 72 insertions(+), 2 deletions(-)
>
> 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,
>  };
> +
> +#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
> +    */
> +   get_cpuid(buffer, sizeof(buffer));
> +   ret = sscanf(buffer, "%u,", &version);
> +
> +   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;
> +}
> --
> 1.8.3.1
>
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