Em Fri, Feb 19, 2021 at 07:05:59PM +0900, Namhyung Kim escreveu: > On Wed, Feb 17, 2021 at 9:58 PM Arnaldo Carvalho de Melo <a...@kernel.org> > wrote: > > Em Fri, Jan 08, 2021 at 02:51:44PM +0900, Namhyung Kim escreveu: > > > On Wed, Jan 6, 2021 at 10:33 AM Namhyung Kim <namhy...@kernel.org> wrote:
> > > As you said, I think mostly we don't care as the accesses will happen > > > in a short period of time. But if you really care, maybe for the upcoming > > > perf daemon changes, I think we can add an API to invalidate the cache > > > or internal time-based invalidation logic (like remove it after 10 sec.). > > Ok, we can have something in 'perf daemon' to periodically invalidate > > this, maybe do a poor man inotify and when asking for the cgroup > > mountpoint, check some characteristic of that file that changes when it > > is modified, or plain use a timestamp and have some threshold. > I thought about this again. > We don't directly access the cgroups in the perf daemon. It just > creates new record processes so they'll see a new mountpoint whenever > they started since this cache is shared within the process only. > That means we don't need to care about the invalidate in the daemon > but each perf record and perf stat should do it when they are required > to do the work repeatedly. > But looking at the code, the cgroup is set during event parsing (-G > option) or early in the command (--for-each-cgroup option). So cgroup > info would not be changed even if the command runs repeatedly. > So I think you can take the patch as is. Its in perf/core branch on its way to Linus soon :-) Thanks for checking it. - Arnaldo
