Messages in this thread | | | Subject | Re: [PATCH v1] perf stat: avoid 10ms limit for printing event counts | From | Alexey Budankov <> | Date | Tue, 27 Mar 2018 14:40:29 +0300 |
| |
On 27.03.2018 12:06, Andi Kleen wrote: >> When running perf stat -I for monitoring e.g. PCIe uncore counters and >> at the same time profiling some I/O workload by perf record e.g. for >> cpu-cycles and context switches, it is then possible to build and >> observe good-enough consolidated CPU/OS/IO(Uncore) performance picture >> for that workload. > > At some point I still hope we can make uncore measurements in > perf record work. Kan tried at some point to allow multiple > PMUs in a group, but was not successfull. But perhaps we > can sample them from a software event instead. > >> >> The warning on possible runtime overhead is still preserved, however >> it is only visible when specifying -v option. > > I would print it unconditionally. Very few people use -v. > > BTW better of course would be to occasionally measure the perf stat > cpu time and only print the warning if it's above some percentage > of a CPU. But that would be much more work.
Would you please elaborate more on that?
Thanks, Alexey
> > Rest looks ok. > > > -Andi >
| |