diff options
| -rw-r--r-- | Documentation/trace/coresight/coresight.rst | 41 | ||||
| -rw-r--r-- | Documentation/userspace-api/perf_ring_buffer.rst | 4 |
2 files changed, 18 insertions, 27 deletions
diff --git a/Documentation/trace/coresight/coresight.rst b/Documentation/trace/coresight/coresight.rst index d4f93d6a2d63..806699871b80 100644 --- a/Documentation/trace/coresight/coresight.rst +++ b/Documentation/trace/coresight/coresight.rst @@ -462,44 +462,35 @@ queried by the perf command line tool: 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. -On newer kernels the available sinks are listed in sysFS under +provided along with configuration options within forward slashes '/' (see +`Config option formats`_). + +Advanced Perf framework usage +----------------------------- + +Sink selection +~~~~~~~~~~~~~~ + +An appropriate sink will be selected automatically for use with Perf, but since +there will typically be more than one sink, the name of the sink to use may be +specified as a special config option prefixed with '@'. + +The available sinks are listed in sysFS under ($SYSFS)/bus/event_source/devices/cs_etm/sinks/:: root@localhost:/sys/bus/event_source/devices/cs_etm/sinks# ls tmc_etf0 tmc_etr0 tpiu0 -On older kernels, this may need to be found from the list of coresight devices, -available under ($SYSFS)/bus/coresight/devices/:: - - root:~# ls /sys/bus/coresight/devices/ - etm0 etm1 etm2 etm3 etm4 etm5 funnel0 - funnel1 funnel2 replicator0 stm0 tmc_etf0 tmc_etr0 tpiu0 root@linaro-nano:~# perf record -e cs_etm/@tmc_etr0/u --per-thread program -As mentioned above in section "Device Naming scheme", the names of the devices could -look different from what is used in the example above. One must use the device names -as it appears under the sysFS. - -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 [#third]_. -Advanced perf framework usage ------------------------------ - AutoFDO analysis using the perf tools ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -508,7 +499,7 @@ perf can be used to record and analyze trace of programs. Execution can be recorded using 'perf record' with the cs_etm event, specifying the name of the sink to record to, e.g:: - perf record -e cs_etm/@tmc_etr0/u --per-thread + perf record -e cs_etm//u --per-thread The 'perf report' and 'perf script' commands can be used to analyze execution, synthesizing instruction and branch events from the instruction trace. @@ -572,7 +563,7 @@ sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tuto Bubble sorting array of 30000 elements 5910 ms - $ perf record -e cs_etm/@tmc_etr0/u --per-thread taskset -c 2 ./sort + $ perf record -e cs_etm//u --per-thread taskset -c 2 ./sort Bubble sorting array of 30000 elements 12543 ms [ perf record: Woken up 35 times to write data ] diff --git a/Documentation/userspace-api/perf_ring_buffer.rst b/Documentation/userspace-api/perf_ring_buffer.rst index bde9d8cbc106..dc71544532ce 100644 --- a/Documentation/userspace-api/perf_ring_buffer.rst +++ b/Documentation/userspace-api/perf_ring_buffer.rst @@ -627,7 +627,7 @@ regular ring buffer. AUX events and AUX trace data are two different things. Let's see an example:: - perf record -a -e cycles -e cs_etm/@tmc_etr0/ -- sleep 2 + perf record -a -e cycles -e cs_etm// -- sleep 2 The above command enables two events: one is the event *cycles* from PMU and another is the AUX event *cs_etm* from Arm CoreSight, both are saved @@ -766,7 +766,7 @@ only record AUX trace data at a specific time point which users are interested in. E.g. below gives an example of how to take snapshots with 1 second interval with Arm CoreSight:: - perf record -e cs_etm/@tmc_etr0/u -S -a program & + perf record -e cs_etm//u -S -a program & PERFPID=$! while true; do kill -USR2 $PERFPID |