On Mon, Dec 12, 2016 at 11:32:09AM -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Dec 12, 2016 at 11:35:42AM +0100, Jiri Olsa escreveu: > > Adding perf_evsel::ignore_missing_cpu_thread bool. > > > > When set true, it allows perf to ignore error of missing > > pid of perf event syscall. > > > > We remove missing thread id from the thread_map, so the > > rest of the processing like ioctl and mmap won't get > > disturbed with -1 fd > > What was the test performed? I tried it here the following while doing > a 'make -j4 allmodconfig' in the background, i.e. tons of threads coming > and going, and I sometimes get: > > [root@jouet ~]# perf record -u acme > Error: > The sys_perf_event_open() syscall returned with 3 (No such process) for > event (cycles:ppp). > /bin/dmesg may provide additional information. > No CONFIG_PERF_EVENTS=y kernel support configured?
I dont think it's fast enough (start/stop) to hit the race, I've got best results with having on background this: while :; do /usr/bin/true; done jirka
