Andi Kleen <a...@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. Regards, -- Alex