Hi Suzuki, On Thu, May 30, 2019 at 04:11:17PM +0100, Suzuki K Poulose wrote: > Update the documentation to reflect the new naming scheme with > latest changes. > > Reported-by: Leo Yan <leo....@linaro.org> > Cc: Mathieu Poirier <mathieu.poir...@linaro.org> > Cc: Jonathan Corbet <cor...@lwn.net> > Signed-off-by: Suzuki K Poulose <suzuki.poul...@arm.com> > --- > Documentation/trace/coresight.txt | 34 +++++++++++++++++++--------------- > 1 file changed, 19 insertions(+), 15 deletions(-) > > diff --git a/Documentation/trace/coresight.txt > b/Documentation/trace/coresight.txt > index efbc832..7b427cf 100644 > --- a/Documentation/trace/coresight.txt > +++ b/Documentation/trace/coresight.txt > @@ -326,16 +326,20 @@ 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 ($SYSFS)/bus/coresight/devices: > +work with needs to be specified as an event option. > +On newer kernels the available sinks are listed in sysFS under: > +($SYSFS)/bus/event_source/devices/cs_etm/sinks/ > > - 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@localhost:/sys/bus/event_source/devices/cs_etm/sinks# ls > + tmc_etf0 tmc_etr0 tpiu0 > > - root@linaro-nano:~# perf record -e cs_etm/@20070000.etr/u --per-thread > program > +On older kernels, this may need to be found from the list of coresight > devices, > +available under ($SYSFS)/bus/coresight/devices/: > + > + root@localhost:/sys/bus/coresight/devices# ls > + 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
On the "older" kernels you are referring to one would find the original naming convention. Everything else looks good to me. Mathieu > > 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 > @@ -352,7 +356,7 @@ 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/@20070000.etr/u --per-thread > + perf record -e cs_etm/@tmc_etr0/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. > @@ -381,7 +385,7 @@ 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/@20070000.etr/u --per-thread taskset -c 2 ./sort > + $ perf record -e cs_etm/@tmc_etr0/u --per-thread taskset -c 2 ./sort > Bubble sorting array of 30000 elements > 12543 ms > [ perf record: Woken up 35 times to write data ] > @@ -405,7 +409,7 @@ 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 > +root@genericarmv8:~# ls /sys/bus/coresight/devices/stm0 > enable_source hwevent_select port_enable subsystem uevent > hwevent_enable mgmt port_select traceid > root@genericarmv8:~# > @@ -413,14 +417,14 @@ 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 > +root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink > +root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/stm0/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:~# ls -l /dev/stm0 > +crw------- 1 root root 10, 61 Jan 3 18:11 /dev/stm0 > root@genericarmv8:~# > > Details on how to use the generic STM API can be found here [2]. > -- > 2.7.4 >
