linux-kernel - Re: [PATCH v5 13/14] coresight: events: PERF_RECORD_AUX_OUTPUT_HW

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Message-ID: <994b80f8-5c92-f82c-d43a-cc24fb002c98@arm.com>
Date:   Tue, 8 Nov 2022 22:49:16 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Mike Leach <mike.leach@...aro.org>, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     mathieu.poirier@...aro.org, peterz@...radead.org, mingo@...hat.com,
        acme@...nel.org, linux-perf-users@...r.kernel.org,
        leo.yan@...aro.org, quic_jinlmao@...cinc.com
Subject: Re: [PATCH v5 13/14] coresight: events: PERF_RECORD_AUX_OUTPUT_HW_ID
 used for Trace ID

On 01/11/2022 16:31, Mike Leach wrote:
> Use the perf_report_aux_output_id() call to output the CoreSight trace ID
> and associated CPU as a PERF_RECORD_AUX_OUTPUT_HW_ID record in the
> perf.data file.
> 
> Signed-off-by: Mike Leach <mike.leach@...aro.org>

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

> ---
>   drivers/hwtracing/coresight/coresight-etm-perf.c |  7 +++++++
>   include/linux/coresight-pmu.h                    | 14 ++++++++++++++
>   2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
> index 6166f716a6ac..59a2ad95c1dc 100644
> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c
> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
> @@ -4,6 +4,7 @@
>    * Author: Mathieu Poirier <mathieu.poirier@...aro.org>
>    */
>   
> +#include <linux/bitfield.h>
>   #include <linux/coresight.h>
>   #include <linux/coresight-pmu.h>
>   #include <linux/cpumask.h>
> @@ -448,6 +449,7 @@ static void etm_event_start(struct perf_event *event, int flags)
>   	struct perf_output_handle *handle = &ctxt->handle;
>   	struct coresight_device *sink, *csdev = per_cpu(csdev_src, cpu);
>   	struct list_head *path;
> +	u64 hw_id;
>   
>   	if (!csdev)
>   		goto fail;
> @@ -493,6 +495,11 @@ static void etm_event_start(struct perf_event *event, int flags)
>   	if (source_ops(csdev)->enable(csdev, event, CS_MODE_PERF))
>   		goto fail_disable_path;
>   
> +	/* output cpu / trace ID in perf record */
> +	hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, CS_AUX_HW_ID_CURR_VERSION) |
> +		FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, coresight_trace_id_read_cpu_id(cpu));

super minor nit: You may split this for better readability.

	traceid = coresight_trace_id_read_cpu_id(cpu);

	hw_id = FIELD_PREP(CS_AUX_HW_ID_VERSION_MASK, CS_AUX_HW_ID_CURR_VERSION);
	hw_id |= FIELD_PREP(CS_AUX_HW_ID_TRACE_ID_MASK, traceid);


Either ways,

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