diff options
| -rw-r--r-- | Documentation/trace/coresight.txt | 72 |
1 files changed, 36 insertions, 36 deletions
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt index ab0d0f2d5cec..1d74ad0202b6 100644 --- a/Documentation/trace/coresight.txt +++ b/Documentation/trace/coresight.txt @@ -345,42 +345,7 @@ 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 -------------------------- - -Using the System Trace Macrocell module is the same as the tracers - the only -difference is that clients are driving the trace capture rather -than the program flow through the code. - -As with any other CoreSight component, specifics about the STM tracer can be -found in sysfs with more information on each entry being found in [1]: - -root@genericarmv8:~# ls /sys/bus/coresight/devices/20100000.stm -enable_source hwevent_select port_enable subsystem uevent -hwevent_enable mgmt port_select traceid -root@genericarmv8:~# - -Like any other source a sink needs to be identified and the STM enabled before -being used: - -root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20010000.etf/enable_sink -root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20100000.stm/enable_source - -From there user space applications can request and use channels using the devfs -interface provided for that purpose by the generic STM API: - -root@genericarmv8:~# ls -l /dev/20100000.stm -crw------- 1 root root 10, 61 Jan 3 18:11 /dev/20100000.stm -root@genericarmv8:~# - -Details on how to use the generic STM API can be found here [2]. - -[1]. Documentation/ABI/testing/sysfs-bus-coresight-devices-stm -[2]. Documentation/trace/stm.txt - - -Using perf tools ----------------- +2.1) AutoFDO analysis using the perf tools: perf can be used to record and analyze trace of programs. @@ -428,3 +393,38 @@ sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tuto $ taskset -c 2 ./sort_autofdo Bubble sorting array of 30000 elements 5806 ms + + +How to use the STM module +------------------------- + +Using the System Trace Macrocell module is the same as the tracers - the only +difference is that clients are driving the trace capture rather +than the program flow through the code. + +As with any other CoreSight component, specifics about the STM tracer can be +found in sysfs with more information on each entry being found in [1]: + +root@genericarmv8:~# ls /sys/bus/coresight/devices/20100000.stm +enable_source hwevent_select port_enable subsystem uevent +hwevent_enable mgmt port_select traceid +root@genericarmv8:~# + +Like any other source a sink needs to be identified and the STM enabled before +being used: + +root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20010000.etf/enable_sink +root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20100000.stm/enable_source + +From there user space applications can request and use channels using the devfs +interface provided for that purpose by the generic STM API: + +root@genericarmv8:~# ls -l /dev/20100000.stm +crw------- 1 root root 10, 61 Jan 3 18:11 /dev/20100000.stm +root@genericarmv8:~# + +Details on how to use the generic STM API can be found here [2]. + +[1]. Documentation/ABI/testing/sysfs-bus-coresight-devices-stm +[2]. Documentation/trace/stm.txt +[3]. https://github.com/Linaro/perf-opencsd |