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23dc4f1586
Enable perf_evsel::ignore_missing_thread for -u option to ignore complete failure if any of the user's processes die between its enumeration and time we open the event. Committer notes: While doing a 'make -j4 allmodconfig' we sometimes get into the race: Before: # 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? # After: [root@jouet ~]# perf record -u acme WARNING: Ignored open failure for pid 9888 WARNING: Ignored open failure for pid 18059 [root@jouet ~]# Which is an improvement, with the races not preventing the remaining threads for the specified user from being monitored, but the message probably needs further clarification. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1481538943-21874-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.