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From: James Clark <james.clark@arm.com>
To: linux-perf-users@vger.kernel.org,
	gankulkarni@os.amperecomputing.com,
	scclevenger@os.amperecomputing.com, coresight@lists.linaro.org,
	suzuki.poulose@arm.com, mike.leach@linaro.org
Cc: James Clark <james.clark@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	John Garry <john.g.garry@oracle.com>,
	Will Deacon <will@kernel.org>, Leo Yan <leo.yan@linux.dev>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	linux-stm32@st-md-mailman.stormreply.com
Subject: [PATCH 09/17] coresight: Clarify comments around the PID of the sink owner
Date: Mon, 29 Apr 2024 16:21:54 +0100	[thread overview]
Message-ID: <20240429152207.479221-10-james.clark@arm.com> (raw)
In-Reply-To: <20240429152207.479221-1-james.clark@arm.com>

"Process being monitored" and "pid of the process to monitor" imply that
this would be the same PID if there were two sessions targeting the same
process. But this is actually the PID of the process that did the Perf
event open call, rather than the target of the session. So update the
comments to make this clearer.

Signed-off-by: James Clark <james.clark@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 5 +++--
 drivers/hwtracing/coresight/coresight-tmc.h     | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index e75428fa1592..8962fc27d04f 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -36,7 +36,8 @@ struct etr_buf_hw {
  * etr_perf_buffer - Perf buffer used for ETR
  * @drvdata		- The ETR drvdaga this buffer has been allocated for.
  * @etr_buf		- Actual buffer used by the ETR
- * @pid			- The PID this etr_perf_buffer belongs to.
+ * @pid			- The PID of the session owner that etr_perf_buffer
+ *			  belongs to.
  * @snaphost		- Perf session mode
  * @nr_pages		- Number of pages in the ring buffer.
  * @pages		- Array of Pages in the ring buffer.
@@ -1662,7 +1663,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
 		goto unlock_out;
 	}
 
-	/* Get a handle on the pid of the process to monitor */
+	/* Get a handle on the pid of the session owner */
 	pid = etr_perf->pid;
 
 	/* Do not proceed if this device is associated with another session */
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index c77763b49de0..2671926be62a 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -171,8 +171,9 @@ struct etr_buf {
  * @csdev:	component vitals needed by the framework.
  * @miscdev:	specifics to handle "/dev/xyz.tmc" entry.
  * @spinlock:	only one at a time pls.
- * @pid:	Process ID of the process being monitored by the session
- *		that is using this component.
+ * @pid:	Process ID of the process that owns the session that is using
+ *		this component. For example this would be the pid of the Perf
+ *		process.
  * @buf:	Snapshot of the trace data for ETF/ETB.
  * @etr_buf:	details of buffer used in TMC-ETR
  * @len:	size of the available trace for ETF/ETB.
-- 
2.34.1


  parent reply	other threads:[~2024-04-29 15:24 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-29 15:21 [PATCH 00/17] coresight: Use per-sink trace ID maps for Perf sessions James Clark
2024-04-29 15:21 ` [PATCH 01/17] perf cs-etm: Print error for new PERF_RECORD_AUX_OUTPUT_HW_ID versions James Clark
2024-05-07  3:47   ` Anshuman Khandual
2024-05-07 10:06     ` James Clark
2024-05-07 10:57       ` Anshuman Khandual
2024-05-07 14:54         ` Arnaldo Carvalho de Melo
2024-04-29 15:21 ` [PATCH 02/17] perf auxtrace: Allow number of queues to be specified James Clark
2024-04-30  6:36   ` Adrian Hunter
2024-05-07  4:26   ` Anshuman Khandual
2024-04-29 15:21 ` [PATCH 03/17] perf: cs-etm: Create decoders after both AUX and HW_ID search passes James Clark
2024-04-29 15:21 ` [PATCH 04/17] perf: cs-etm: Allocate queues for all CPUs James Clark
2024-04-29 15:21 ` [PATCH 05/17] perf: cs-etm: Move traceid_list to each queue James Clark
2024-04-29 15:21 ` [PATCH 06/17] perf: cs-etm: Create decoders based on the trace ID mappings James Clark
2024-04-29 15:21 ` [PATCH 07/17] perf: cs-etm: Support version 0.1 of HW_ID packets James Clark
2024-04-29 15:21 ` [PATCH 08/17] coresight: Remove unused stubs James Clark
2024-05-01 11:06   ` Mike Leach
2024-05-07  4:15   ` Anshuman Khandual
2024-04-29 15:21 ` James Clark [this message]
2024-05-01 11:07   ` [PATCH 09/17] coresight: Clarify comments around the PID of the sink owner Mike Leach
2024-05-07  4:25   ` Anshuman Khandual
2024-04-29 15:21 ` [PATCH 10/17] coresight: Move struct coresight_trace_id_map to common header James Clark
2024-05-01 11:11   ` Mike Leach
2024-05-07  5:50   ` Anshuman Khandual
2024-04-29 15:21 ` [PATCH 11/17] coresight: Expose map argument in trace ID API James Clark
2024-05-01 10:31   ` Mike Leach
2024-05-17 10:09     ` James Clark
2024-05-07  6:00   ` Anshuman Khandual
2024-04-29 15:21 ` [PATCH 11/17] coresight: Expose map arugment " James Clark
2024-04-29 15:30   ` James Clark
2024-04-29 15:21 ` [PATCH 12/17] coresight: Make CPU id map a property of a trace ID map James Clark
2024-05-07  6:22   ` Anshuman Khandual
2024-05-07  9:57     ` James Clark
2024-04-29 15:21 ` [PATCH 13/17] coresight: Pass trace ID map into source enable James Clark
2024-05-07  6:46   ` Anshuman Khandual
2024-05-07 10:49   ` Suzuki K Poulose
2024-04-29 15:22 ` [PATCH 14/17] coresight: Use per-sink trace ID maps for Perf sessions James Clark
2024-05-03  9:43   ` Mike Leach
2024-05-03 14:31     ` James Clark
2024-05-07 10:52   ` Suzuki K Poulose
2024-05-17 10:07     ` James Clark
2024-04-29 15:22 ` [PATCH 15/17] coresight: Remove pending trace ID release mechanism James Clark
2024-04-29 15:22 ` [PATCH 16/17] coresight: Re-emit trace IDs when the sink changes in per-thread mode James Clark
2024-05-07 11:05   ` Suzuki K Poulose
2024-05-17 10:01     ` James Clark
2024-04-29 15:22 ` [PATCH 17/17] coresight: Emit HW_IDs for all ETMs that are using the sink James Clark
2024-05-03 12:40 ` [PATCH 00/17] coresight: Use per-sink trace ID maps for Perf sessions Mike Leach
2024-05-17 10:45   ` James Clark
2024-05-03 20:23 ` Arnaldo Carvalho de Melo
2024-05-07 10:01   ` James Clark
2024-05-07 14:59     ` Arnaldo Carvalho de Melo
2024-05-07 11:02 ` Ganapatrao Kulkarni

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