Re: [PATCHSET 0/8] perf tools: Fix scalability problem on callchainmerging (v5)

[Jiri Olsa]

On Fri, Oct 11, 2013 at 07:58:29AM +0200, Ingo Molnar wrote:
> 
> * Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> 
> > Hello,
> > 
> > This is a new version of callchain improvement patchset.  Basically
> > it's almost same as v4 but rebased on current acme/perf/core and some
> > functions are renamed as Frederic requested.
> > 
> > Now I'm hunting down a bug in 'perf report -s sym' which was found
> > during the test, but I think it's not related to this change as it can
> > be reproduced in earlier versions too.
> > 
> > I put this series on 'perf/callchain-v5' branch in my tree
> > 
> >   git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
> > 
> > Any comments are welcome, thanks.
> 
> One thing I noticed about call-graph profiling:
> 
>   comet:~/tip/tools/perf> ./perf record -g ~/hackbench 10
>   callchain: Unknown -g option value: /home/mingo/hackbench
> 
> I think a naked -g used to work just fine in the past. Even if such an 
> error is displayed the output is very unhelpful, it does does a full 
> perf-record options dump (unnecessary), the bit that is helpful is hidden 
> amongst many other options:
> 
>     -g, --call-graph <mode[,dump_size]>
>                           do call-graph (stack chain/backtrace) recording: [fp] dwarf
> 
> and it took me two reads to see that I should specify 'fp'. The '[fp]' 
> indicates that fp is the default - but that does not appear to be working.

'-g' takes optional parameter, so having it in front of
non option string is causing the error, you could use:

./perf record -g -- ~/hackbench 10

maybe we could display just only help string of the option
we failed to process in this case

jirka
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