On Thu, Oct 22, 2015 at 5:46 PM, Ingo Molnar <[email protected]> wrote: > > * Arnaldo Carvalho de Melo <[email protected]> wrote: > >> > 5) --no-children >> > >> > I agree that 'perf top -g --no-children' looks more intuitive than 'perf >> > top -g'. >> >> So, what do you propose, to switch back the default to --no-children, for >> both >> tools, top and report? Now that I am getting used to it... ;-) > > Heh ;-) So I'm only thinking out loud, trying to find the most intuitive > initial > screen to display. Expert users can configure their output any which way they > want > it to be, I'm not worried about them.
:) > > It's casual and in particular first-time users we should be worried about > most - > if they try the '-g' option in record, what will they first see in 'perf > report' > output? > > I think the best output method would be to include only the 'highest level' > parent > symbols, with all children summed up under the parent's entry. Isn't the new > 'graph,0.5,caller' default very close to that? Hmm.. not sure I'm following well. what do you mean by 'highest level parent'? Do you want single depth callchains for each entry? > > But what confuses me about the output is the same that confused Wangnan's > users: > > "This is my story: after switching to new version of perf, in a period of > time > there are plenty of perf users in my company be confused by the first > column of > 'perf report' because the sum of the percentage listed there is much > higher than > 100%. They find me because they think this is a bug in perf which breaks > their > routinely profiling work." > > So this is suboptimal. > > The first column is 'Children', which should show the sum of all child > overhead - > but if a child overhead was already included under a parent, it should never > show > up under another parent's entry. I.e. the first column should only contain the > highest level entries, no sub-entries. Again, I don't understand. Could you elaborate it more probably with example below? > > But what we do currently is: > > Children Self Command Shared Object Symbol > - 70.41% 0.00% cc1 cc1 [.] toplev_main > - toplev_main > + __libc_start_main > - 70.38% 0.00% cc1 libc-2.20.so [.] __libc_start_main > + __libc_start_main > > i.e. even though '__libc_start_main' is a child of 'toplev_main', it's still > included on the 'overview' page. Strange. AFAIK 'toplev_main' is a child of '__libc_start_main'. Are you using 'caller' ordering? Also I think 'main' should be shown between 'toplev_main' and '__libc_start_main' but maybe it's a different issue. Thanks, Namhyung > > Is there an output method that can do what I suggest above? > > ( Having both 'children' and 'self' columns in itself is intuitive IMHO: it > shows > that an entry that is shown does not directly have overhead at that level, a > child call of it has that overhead. ) > > Thanks, > > Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
