On 02/28/2018 05:36 PM, Srikar Dronamraju wrote: > * Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> [2018-02-28 13:23:41]: > >> # readelf -n ./tick >> Provider: tick >> Name: loop2 >> ... Semaphore: 0x0000000010020036 >> >> # readelf -SW ./tick | grep probes >> [25] .probes PROGBITS 0000000010020034 010034 >> >> >> Semaphore offset is 0x10036. I don't have educated 'perf probe' >> about semaphore. So instead of using 'perf probe' command, I'm >> manually adding entry in the <tracefs>/uprobe_events file. >> Special char * denotes semaphore offset. >> >> >> # echo "p:sdt_tick/loop2 /tmp/tick:0x6e4 *0x10036" > uprobe_events >> >> # perf stat -e sdt_tick:loop2 -- /tmp/tick >> hi: 0 >> hi: 1 >> hi: 2 >> hi: 3 >> ^C >> Performance counter stats for '/tmp/tick': >> 4 sdt_tick:loop2 >> >> 3.359047827 seconds time elapsed >> >> >> Feedback? >> >> TODO: >> - Educate perf tool about semaphore. >> > Is it possible to extend perf buildcache with a new option to work with > semaphore?
Yes, that should be fairly easy to do. Will add a patch for that. Thanks for the review, Ravi
