linux-kernel - Re: [PATCH] perf tools: Add SPE total latency as PERF_SAMPLE

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Message-ID: <20211201050836.GB2678859@leoy-ThinkPad-X240s>
Date:   Wed, 1 Dec 2021 13:08:36 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>, Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Ian Rogers <irogers@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        German Gomez <german.gomez@....com>,
        Mark Rutland <mark.rutland@....com>,
        James Clark <James.Clark@....com>
Subject: Re: [PATCH] perf tools: Add SPE total latency as PERF_SAMPLE_WEIGHT

Hi Namhyung,

On Tue, Nov 30, 2021 at 04:39:08PM -0800, Namhyung Kim wrote:
> Use total latency info in the SPE counter packet as sample weight so
> that we can see it in local_weight and (global) weight sort keys.
> 
> Maybe we can use PERF_SAMPLE_WEIGHT_STRUCT to support ins_lat as well
> but I'm not sure which latency it matches.  So just adding total
> latency first.
> 
> Cc: German Gomez <german.gomez@....com>
> Cc: Leo Yan <leo.yan@...aro.org>
> Cc: Mark Rutland <mark.rutland@....com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>  tools/perf/util/arm-spe-decoder/arm-spe-decoder.c | 2 ++
>  tools/perf/util/arm-spe-decoder/arm-spe-decoder.h | 1 +
>  tools/perf/util/arm-spe.c                         | 4 +++-
>  3 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> index 3fc528c9270c..5e390a1a79ab 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.c
> @@ -179,6 +179,8 @@ static int arm_spe_read_record(struct arm_spe_decoder *decoder)
>  				decoder->record.phys_addr = ip;
>  			break;
>  		case ARM_SPE_COUNTER:
> +			if (idx == SPE_CNT_PKT_HDR_INDEX_TOTAL_LAT)
> +				decoder->record.latency = payload;
>  			break;
>  		case ARM_SPE_CONTEXT:
>  			decoder->record.context_id = payload;
> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> index 46a8556a9e95..69b31084d6be 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-decoder.h
> @@ -33,6 +33,7 @@ struct arm_spe_record {
>  	enum arm_spe_sample_type type;
>  	int err;
>  	u32 op;
> +	u32 latency;
>  	u64 from_ip;
>  	u64 to_ip;
>  	u64 timestamp;
> diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
> index 4748bcfe61de..a756325c72a7 100644
> --- a/tools/perf/util/arm-spe.c
> +++ b/tools/perf/util/arm-spe.c
> @@ -317,6 +317,7 @@ static int arm_spe__synth_mem_sample(struct arm_spe_queue *speq,
>  	sample.addr = record->virt_addr;
>  	sample.phys_addr = record->phys_addr;
>  	sample.data_src = data_src;
> +	sample.weight = record->latency;

The latency can be used for branch operations as well, it's good to
assign latency for branch samples in the function
arm_spe__synth_branch_sample().

With adding latency for branch sample, the change would be good for me:

Reviewed-by: Leo Yan <leo.yan@...aro.org>

>  	return arm_spe_deliver_synth_event(spe, speq, event, &sample);
>  }
> @@ -980,7 +981,8 @@ arm_spe_synth_events(struct arm_spe *spe, struct perf_session *session)
>  	attr.type = PERF_TYPE_HARDWARE;
>  	attr.sample_type = evsel->core.attr.sample_type & PERF_SAMPLE_MASK;
>  	attr.sample_type |= PERF_SAMPLE_IP | PERF_SAMPLE_TID |
> -			    PERF_SAMPLE_PERIOD | PERF_SAMPLE_DATA_SRC;
> +			    PERF_SAMPLE_PERIOD | PERF_SAMPLE_DATA_SRC |
> +			    PERF_SAMPLE_WEIGHT;
>  	if (spe->timeless_decoding)
>  		attr.sample_type &= ~(u64)PERF_SAMPLE_TIME;
>  	else
> -- 
> 2.34.0.rc2.393.gf8c9666880-goog
>