Re: [PATCH v9 4/5] perf arm-spe: Don't set data source if it's not a memory operation

Arnaldo Carvalho de Melo
2022-06-17T19:42:29Z

Em Tue, May 17, 2022 at 02:03:25AM +0000, Ali Saidi escreveu:
> From: Leo Yan <leo.yan@linaro.org>
>
> Except memory load and store operations, Arm SPE records also can
> support other operation types, bug when set the data source field the
> current code assumes a record is a either load operation or store
> operation, this leads to wrongly synthesize memory samples.
>
> This patch strictly checks the record operation type, it only sets data
> source only for the operation types ARM_SPE_LD and ARM_SPE_ST,
> otherwise, returns zero for data source. Therefore, we can synthesize
> memory samples only when data source is a non-zero value, the function
> arm_spe__is_memory_event() is useless and removed.

Thanks, applied.

- Arnaldo

> Fixes: e55ed3423c1b ("perf arm-spe: Synthesize memory event")
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> Reviewed-by: Ali Saidi <alisaidi@amazon.com>
> Tested-by: Ali Saidi <alisaidi@amazon.com>
> Reviewed-by: German Gomez <german.gomez@arm.com>
> ---
> tools/perf/util/arm-spe.c | 22 ++++++++--------------
> 1 file changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index d2b64e3f588b..e032efc03274 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -387,26 +387,16 @@ static int arm_spe__synth_instruction_sample(struct arm_spe_queue *speq,
> return arm_spe_deliver_synth_event(spe, speq, event, &sample);
> }
>
> -#define SPE_MEM_TYPE (ARM_SPE_L1D_ACCESS | ARM_SPE_L1D_MISS | \
> - ARM_SPE_LLC_ACCESS | ARM_SPE_LLC_MISS | \
> - ARM_SPE_REMOTE_ACCESS)
> -
> -static bool arm_spe__is_memory_event(enum arm_spe_sample_type type)
> -{
> - if (type & SPE_MEM_TYPE)
> - return true;
> -
> - return false;
> -}
> -
> static u64 arm_spe__synth_data_source(const struct arm_spe_record *record)
> {
> union perf_mem_data_src data_src = { 0 };
>
> if (record->op == ARM_SPE_LD)
> data_src.mem_op = PERF_MEM_OP_LOAD;
> - else
> + else if (record->op == ARM_SPE_ST)
> data_src.mem_op = PERF_MEM_OP_STORE;
> + else
> + return 0;
>
> if (record->type & (ARM_SPE_LLC_ACCESS | ARM_SPE_LLC_MISS)) {
> data_src.mem_lvl = PERF_MEM_LVL_L3;
> @@ -510,7 +500,11 @@ static int arm_spe_sample(struct arm_spe_queue *speq)
> return err;
> }
>
> - if (spe->sample_memory && arm_spe__is_memory_event(record->type)) {
> + /*
> + * When data_src is zero it means the record is not a memory operation,
> + * skip to synthesize memory sample for this case.
> + */
> + if (spe->sample_memory && data_src) {
> err = arm_spe__synth_mem_sample(speq, spe->memory_id, data_src);
> if (err)
> return err;
> --
> 2.32.0

--

- Arnaldo