linux-kernel - Re: [PATCH v1 5/7] perf cs-etm: Fixup PID

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Date:   Mon, 11 Jan 2021 09:47:31 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Leo Yan <leo.yan@...aro.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Mike Leach <mike.leach@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        John Garry <john.garry@...wei.com>,
        Will Deacon <will@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Daniel Kiss <Daniel.Kiss@....com>,
        Denis Nikitin <denik@...omium.org>, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 5/7] perf cs-etm: Fixup PID_FMT when it is zero

On 1/9/21 7:44 AM, Leo Yan wrote:
> If the metadata item CS_ETM_PID_FMT/CS_ETMV4_PID_FMT is zero, this means
> the perf data file is recorded with old version tool and the tool has
> not extended to support the item.
> 
> For this case, this patch fixes up PID_FMT entry to set the value as
> BIT(ETM_OPT_CTXTID), this info will be delivered to the decoder to
> extract PID from packet's field "context_id".
> 
> Signed-off-by: Leo Yan <leo.yan@...aro.org>

Acked-by: Suzuki K Poulose <suzuki.poulose@....com>

> ---
>   tools/perf/util/cs-etm.c | 19 +++++++++++++++++++
>   1 file changed, 19 insertions(+)
> 
> diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> index 763085db29ae..8c125134a756 100644
> --- a/tools/perf/util/cs-etm.c
> +++ b/tools/perf/util/cs-etm.c
> @@ -7,6 +7,7 @@
>    */
>   
>   #include <linux/bitops.h>
> +#include <linux/coresight-pmu.h>
>   #include <linux/err.h>
>   #include <linux/kernel.h>
>   #include <linux/log2.h>
> @@ -2577,6 +2578,15 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
>   			for (k = 0; k < metadata_cpu_array_size; k++)
>   				metadata[j][k] = ptr[i + k];
>   
> +			/*
> +			 * If the data in CS_ETM_PID_FMT is zero, means the
> +			 * information isn't stored in the data file, this is
> +			 * because the old perf tool hasn't yet supported
> +			 * CS_ETM_PID_FMT.  Fixup the item to option "CTXTID".
> +			 */
> +			if (!metadata[j][CS_ETM_PID_FMT])
> +				metadata[j][CS_ETM_PID_FMT] = BIT(ETM_OPT_CTXTID);
> +
>   			/* The traceID is our handle */
>   			idx = metadata[j][CS_ETM_ETMTRACEIDR];
>   			i += metadata_cpu_array_size;
> @@ -2590,6 +2600,15 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
>   			for (k = 0; k < metadata_cpu_array_size; k++)
>   				metadata[j][k] = ptr[i + k];
>   
> +			/*
> +			 * If the data in CS_ETMV4_PID_FMT is zero, means the
> +			 * information isn't stored in the data file, this is
> +			 * because the old perf tool hasn't yet supported
> +			 * CS_ETMV4_PID_FMT.  Fixup the item to option "CTXTID".
> +			 */
> +			if (!metadata[j][CS_ETMV4_PID_FMT])
> +				metadata[j][CS_ETMV4_PID_FMT] = BIT(ETM_OPT_CTXTID);
> +
>   			/* The traceID is our handle */
>   			idx = metadata[j][CS_ETMV4_TRCTRACEIDR];
>   			i += metadata_cpu_array_size;
>