Messages in this thread | | | Date | Thu, 11 Sep 2014 18:30:27 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: perf top -g -U --sort=symbol --children == lalalalala? |
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Em Thu, Sep 11, 2014 at 10:43:38AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Sep 11, 2014 at 02:43:12PM +0200, Mike Galbraith escreveu: > > On Thu, 2014-09-11 at 17:09 +0900, Namhyung Kim wrote: > > > On Tue, Sep 9, 2014 at 10:37 PM, Arnaldo Carvalho de Melo > > > <acme@ghostprotocols.net> wrote: > > > > Em Tue, Sep 09, 2014 at 01:54:01PM +0200, Mike Galbraith escreveu: > > > >> Seems the now default on --children thingy doesn't like -U much.
> > > > Namhyung, can you please take a look at this?
> > > So what is the problem here?
> > Well, if you don't see anything wrong, I guess nothing at all.
> :-)
> I think that when we decide that it is so better to change defaults like > we did this time, we should be required to add a big fat warning (a > --tui popup, use the first lines on --stdio, etc) about why the default > was changed and allow quick, easy opt out, restoring previous behaviour > after the user, being warned, knows what to expect, tries it, and then > is in a better position to decide if keeping the new default is what is > desired.
Also, looking at the changelog entries and at tools/perf/Documentation/ the only description for --children, the default, is:
---------------- --children:: Accumulate callchain of children to parent entry so that then can show up in the output. The output will have a new "Children" column and will be sorted on the data. It requires callchains are recorded. ----------------
I think that a longer/clearer entry in the 'perf record' man page is required.
Perhaps the description got lost in a --cover-letter for the patch series implementing it?
- Arnaldo
> > > > >> Samples: 5K of event 'cycles', Event count (approx.): 2268660922 > > > >> Children Self Symbol > > > >> + 46.42% 0.04% [k] system_call_fastpath > > > I'll just turn it off until I figure out what cool stuff this is telling > > me. why that symbol becomes the number one hit, and why total% > 100. > > > To me, it looks like top smoked it's breakfast, went to lala land ;-) > > Yeah, its confusing, I'll let Namhyung explain it ;-) > > :-) > > - Arnaldo
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