Em Mon, Dec 12, 2016 at 03:53:12PM +0100, Jiri Olsa escreveu: > 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
Ok, but the focus of my message wasn't on generating threads, was in having the above happen with your patch applied. - Arnaldo
