Messages in this thread | | | From | Namhyung Kim <> | Date | Tue, 27 Oct 2020 13:45:43 +0900 | Subject | Re: [RFC] perf evlist: Warn if event group has mixed sw/hw events |
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Hi,
On Tue, Oct 27, 2020 at 12:49 AM Alexander Shishkin <alexander.shishkin@linux.intel.com> wrote: > > Andi Kleen <ak@linux.intel.com> writes: > > > On Mon, Oct 26, 2020 at 11:19:37PM +0900, Namhyung Kim wrote: > >> This patch just added a warning before running it. I'd really want to > >> fix the kernel if possible but don't have a good idea. Thoughts? > > > > The easiest fix would be some multi threading in perf stat opening, then then > > extra latencies could be mostly hidden. One thread per group would probably > > be overkill, but just a few threads would lower the penalty significantly. > > > > I think that would be better than this patch and it's likely not that much > > more complicated, as this is already a lot of code. > > > >> +{ > >> + const char *known_sw_pmu[] = { > >> + "software", "tracepoint", "breakpoint", "kprobe", "uprobe", "msr" > > > > That's a non scalable approach. New pmus get added regularly. It would be better to > > indicate this in a generic way from the kernel. > > That, and also, intel_pt is a software PMU and a few of its features > depend on intel_pt/.../ being a group leader.
Thanks for the info, that's good to know.
So do you mean intel_pt requires other HW events in the same group?
Thanks Namhyung
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