On Wed, Feb 19, 2014 at 04:00:45PM +0100, Manuel Selva wrote: > Hi all, > > I just tried in a 2-threaded application to call twice (one call for > each thread) perf_event_open syscall with parameters configured to do > sampling on MEM INST RETIRED.LATENCY ABOVE THRESHOLD event. Both call > succeed. > > "mmaping" the file descriptor return by the first call succeed but > "mmaping" the second file descriptor results in a "Operation not > permitted" error (errno = 1).
seems like you might have crossed the perf mem user limit? [jolsa@krava ~]$ sysctl kernel.perf_event_mlock_kb kernel.perf_event_mlock_kb = 516 you can either split the memory amount between those threads or you can increase that limit.. or run your app under root ;-) jirka >mit > A work around could be to sample all threads (with pid = -1) including > pid and tid in samples and filter samples at processing time. Before > switching to this solution I wanted to ask if this a known limitation > of the syscall, an error from my side, or a bug (the man page doesn't > answer to this question) ? > > Thanks, > > Manu > -- > To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
