From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: linux-arm-kernel@lists.infradead.org, corbet@lwn.net
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
rdunlap@infradead.org, Ben.Gainey@arm.com
Subject: [PATCH v2 2/3] coresight: Add section for integration with the perf tools
Date: Tue, 17 Apr 2018 10:08:06 -0600 [thread overview]
Message-ID: <1523981287-15370-3-git-send-email-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <1523981287-15370-1-git-send-email-mathieu.poirier@linaro.org>
Adding a section that document how to use the Coresight framework and
drivers from the perf tools.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
Documentation/trace/coresight.txt | 52 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 51 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 710c75b6c73f..ab0d0f2d5cec 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.txt
@@ -187,10 +187,19 @@ that can be performed on them (see "struct coresight_ops"). The
specific to that component only. "Implementation defined" customisations are
expected to be accessed and controlled using those entries.
+
How to use the tracer modules
-----------------------------
-Before trace collection can start, a coresight sink needs to be identify.
+There are two ways to use the Coresight framework: 1) using the perf cmd line
+tools and 2) interacting directly with the Coresight devices using the sysFS
+interface. Preference is given to the former as using the sysFS interface
+requires a deep understanding of the Coresight HW. The following sections
+provide details on using both methods.
+
+1) Using the sysFS interface:
+
+Before trace collection can start, a coresight sink needs to be identified.
There is no limit on the amount of sinks (nor sources) that can be enabled at
any given moment. As a generic operation, all device pertaining to the sink
class will have an "active" entry in sysfs:
@@ -295,6 +304,47 @@ Instruction 13570831 0x8026B584 E28DD00C false ADD
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
+2) Using perf framework:
+
+Coresight tracers are represented using the Perf framework's Performance
+Monitoring Unit (PMU) abstraction. As such the perf framework takes charge of
+controlling when tracing gets enabled based on when the process of interest is
+scheduled. When configured in a system, Coresight PMUs will be listed when
+queried by the perf command line tool:
+
+ linaro@linaro-nano:~$ ./perf list pmu
+
+ List of pre-defined events (to be used in -e):
+
+ cs_etm// [Kernel PMU event]
+
+ linaro@linaro-nano:~$
+
+Regardless of the number of tracers available in a system (usually equal to the
+amount of processor cores), the "cs_etm" PMU will be listed only once.
+
+A Coresight PMU works the same way as any other PMU, i.e the name of the PMU is
+listed along with configuration options within forward slashes '/'. Since a
+Coresight system will typically have more than one sink, the name of the sink to
+work with needs to be specified as an event option. Names for sink to choose
+from are listed in sysFS under ($SYSFS)/bus/coresight/devices:
+
+ root@linaro-nano:~# ls /sys/bus/coresight/devices/
+ 20010000.etf 20040000.funnel 20100000.stm 22040000.etm
+ 22140000.etm 230c0000.funnel 23240000.etm 20030000.tpiu
+ 20070000.etr 20120000.replicator 220c0000.funnel
+ 23040000.etm 23140000.etm 23340000.etm
+
+ root@linaro-nano:~# perf record -e cs_etm/@20070000.etr/u --per-thread program
+
+The syntax within the forward slashes '/' is important. The '@' character
+tells the parser that a sink is about to be specified and that this is the sink
+to use for the trace session.
+
+More information on the above and other example on how to use Coresight with
+the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
+repository [3].
+
How to use the STM module
-------------------------
--
2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: linux-arm-kernel@lists.infradead.org, corbet@lwn.net
Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
rdunlap@infradead.org, Ben.Gainey@arm.com
Subject: [PATCH v2 2/3] coresight: Add section for integration with the perf tools
Date: Tue, 17 Apr 2018 10:08:06 -0600 [thread overview]
Message-ID: <1523981287-15370-3-git-send-email-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <1523981287-15370-1-git-send-email-mathieu.poirier@linaro.org>
Adding a section that document how to use the Coresight framework and
drivers from the perf tools.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
Documentation/trace/coresight.txt | 52 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 51 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 710c75b6c73f..ab0d0f2d5cec 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.txt
@@ -187,10 +187,19 @@ that can be performed on them (see "struct coresight_ops"). The
specific to that component only. "Implementation defined" customisations are
expected to be accessed and controlled using those entries.
+
How to use the tracer modules
-----------------------------
-Before trace collection can start, a coresight sink needs to be identify.
+There are two ways to use the Coresight framework: 1) using the perf cmd line
+tools and 2) interacting directly with the Coresight devices using the sysFS
+interface. Preference is given to the former as using the sysFS interface
+requires a deep understanding of the Coresight HW. The following sections
+provide details on using both methods.
+
+1) Using the sysFS interface:
+
+Before trace collection can start, a coresight sink needs to be identified.
There is no limit on the amount of sinks (nor sources) that can be enabled at
any given moment. As a generic operation, all device pertaining to the sink
class will have an "active" entry in sysfs:
@@ -295,6 +304,47 @@ Instruction 13570831 0x8026B584 E28DD00C false ADD
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
+2) Using perf framework:
+
+Coresight tracers are represented using the Perf framework's Performance
+Monitoring Unit (PMU) abstraction. As such the perf framework takes charge of
+controlling when tracing gets enabled based on when the process of interest is
+scheduled. When configured in a system, Coresight PMUs will be listed when
+queried by the perf command line tool:
+
+ linaro@linaro-nano:~$ ./perf list pmu
+
+ List of pre-defined events (to be used in -e):
+
+ cs_etm// [Kernel PMU event]
+
+ linaro@linaro-nano:~$
+
+Regardless of the number of tracers available in a system (usually equal to the
+amount of processor cores), the "cs_etm" PMU will be listed only once.
+
+A Coresight PMU works the same way as any other PMU, i.e the name of the PMU is
+listed along with configuration options within forward slashes '/'. Since a
+Coresight system will typically have more than one sink, the name of the sink to
+work with needs to be specified as an event option. Names for sink to choose
+from are listed in sysFS under ($SYSFS)/bus/coresight/devices:
+
+ root@linaro-nano:~# ls /sys/bus/coresight/devices/
+ 20010000.etf 20040000.funnel 20100000.stm 22040000.etm
+ 22140000.etm 230c0000.funnel 23240000.etm 20030000.tpiu
+ 20070000.etr 20120000.replicator 220c0000.funnel
+ 23040000.etm 23140000.etm 23340000.etm
+
+ root@linaro-nano:~# perf record -e cs_etm/@20070000.etr/u --per-thread program
+
+The syntax within the forward slashes '/' is important. The '@' character
+tells the parser that a sink is about to be specified and that this is the sink
+to use for the trace session.
+
+More information on the above and other example on how to use Coresight with
+the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
+repository [3].
+
How to use the STM module
-------------------------
--
2.7.4
--
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WARNING: multiple messages have this Message-ID (diff)
From: mathieu.poirier@linaro.org (Mathieu Poirier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/3] coresight: Add section for integration with the perf tools
Date: Tue, 17 Apr 2018 10:08:06 -0600 [thread overview]
Message-ID: <1523981287-15370-3-git-send-email-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <1523981287-15370-1-git-send-email-mathieu.poirier@linaro.org>
Adding a section that document how to use the Coresight framework and
drivers from the perf tools.
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
Documentation/trace/coresight.txt | 52 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 51 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 710c75b6c73f..ab0d0f2d5cec 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.txt
@@ -187,10 +187,19 @@ that can be performed on them (see "struct coresight_ops"). The
specific to that component only. "Implementation defined" customisations are
expected to be accessed and controlled using those entries.
+
How to use the tracer modules
-----------------------------
-Before trace collection can start, a coresight sink needs to be identify.
+There are two ways to use the Coresight framework: 1) using the perf cmd line
+tools and 2) interacting directly with the Coresight devices using the sysFS
+interface. Preference is given to the former as using the sysFS interface
+requires a deep understanding of the Coresight HW. The following sections
+provide details on using both methods.
+
+1) Using the sysFS interface:
+
+Before trace collection can start, a coresight sink needs to be identified.
There is no limit on the amount of sinks (nor sources) that can be enabled at
any given moment. As a generic operation, all device pertaining to the sink
class will have an "active" entry in sysfs:
@@ -295,6 +304,47 @@ Instruction 13570831 0x8026B584 E28DD00C false ADD
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
+2) Using perf framework:
+
+Coresight tracers are represented using the Perf framework's Performance
+Monitoring Unit (PMU) abstraction. As such the perf framework takes charge of
+controlling when tracing gets enabled based on when the process of interest is
+scheduled. When configured in a system, Coresight PMUs will be listed when
+queried by the perf command line tool:
+
+ linaro at linaro-nano:~$ ./perf list pmu
+
+ List of pre-defined events (to be used in -e):
+
+ cs_etm// [Kernel PMU event]
+
+ linaro at linaro-nano:~$
+
+Regardless of the number of tracers available in a system (usually equal to the
+amount of processor cores), the "cs_etm" PMU will be listed only once.
+
+A Coresight PMU works the same way as any other PMU, i.e the name of the PMU is
+listed along with configuration options within forward slashes '/'. Since a
+Coresight system will typically have more than one sink, the name of the sink to
+work with needs to be specified as an event option. Names for sink to choose
+from are listed in sysFS under ($SYSFS)/bus/coresight/devices:
+
+ root at linaro-nano:~# ls /sys/bus/coresight/devices/
+ 20010000.etf 20040000.funnel 20100000.stm 22040000.etm
+ 22140000.etm 230c0000.funnel 23240000.etm 20030000.tpiu
+ 20070000.etr 20120000.replicator 220c0000.funnel
+ 23040000.etm 23140000.etm 23340000.etm
+
+ root at linaro-nano:~# perf record -e cs_etm/@20070000.etr/u --per-thread program
+
+The syntax within the forward slashes '/' is important. The '@' character
+tells the parser that a sink is about to be specified and that this is the sink
+to use for the trace session.
+
+More information on the above and other example on how to use Coresight with
+the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
+repository [3].
+
How to use the STM module
-------------------------
--
2.7.4
next prev parent reply other threads:[~2018-04-17 16:31 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-17 16:08 [PATCH v2 0/3] coresight: Refresh documenation Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 16:08 ` [PATCH v2 1/3] coresight: Remove obsolete reference to "owner" in CoreSight descriptor Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier [this message]
2018-04-17 16:08 ` [PATCH v2 2/3] coresight: Add section for integration with the perf tools Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 17:26 ` Randy Dunlap
2018-04-17 17:26 ` Randy Dunlap
2018-04-17 17:26 ` Randy Dunlap
2018-04-17 16:08 ` [PATCH v2 3/3] coresight: Grouping all perf tools oriented section together Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-17 16:08 ` Mathieu Poirier
2018-04-27 23:00 ` [PATCH v2 0/3] coresight: Refresh documenation Jonathan Corbet
2018-04-27 23:00 ` Jonathan Corbet
2018-04-27 23:00 ` Jonathan Corbet
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