Messages in this thread | | | From | Milian Wolff <> | Subject | Re: [PATCH] perf, tools, script: Allow adding and removing fields | Date | Fri, 09 Jun 2017 11:13:11 +0200 |
| |
On Freitag, 9. Juni 2017 04:52:43 CEST Andi Kleen wrote: > On Thu, Jun 08, 2017 at 02:59:58PM +0200, Milian Wolff wrote: > > But I notice that this functionality is missing in other places too. Most > > notably, I would like to be able to configure `perf stat` in a similar > > way. > > Such that one could do: > > > > perf stat -e +cache-misses > > > > Instead of > > > > perf stat -e <whatever the defaults are>,cache-misses > > The defaults are not great, so I'm not sure that is super useful. > > It's probably better to assemble reasonable groups, perhaps > with groups of metrics. > > > But I cannot do: > > > > $ perf record -e "topdown-*" ls > > event syntax error: 'topdown-*' > > That's actually good because the current topdown events are not useful to > sample
Can you elaborate? I assume it's because you actually want to sample on instructions, and then group it together with the topdown events and potentially other counters like instructions?
> Usually you need to have at least some idea about the events you're > collecting, and also for non trivial collections you need groups to get > good results.
Yes, sure. But replace `record` with `stat` in the above and my point still stands.
> I've been thinking about adding MetricGroups to the json files, that > would allow to assemble reasonable groups. But it still wouldn't be > wildcard. > > For a few things wildcards are useful, e.g. I implemented it recently > for PMUs so that uncore PMUs are easier to handle.
I just noticed that I can actually use wildcards for tracepoints:
perf trace --no-syscalls --event "ext4:*"
And I think the same should be doable for PMU events with perf stat, but currently isn't:
$ perf stat -e "topdown*" ls invalid or unsupported event: 'topdown*' $ perf stat -e "branch*" ls invalid or unsupported event: 'branch*' $ perf stat -e "cache*" ls invalid or unsupported event: 'cache*'
Bye
-- Milian Wolff | milian.wolff@kdab.com | Software Engineer KDAB (Deutschland) GmbH&Co KG, a KDAB Group company Tel: +49-30-521325470 KDAB - The Qt Experts
| |