Re: [PATCH 2/2] perf hist: Don't fprintf the callgraphunconditionally

From: Frederic Weisbecker
Date: Sun Mar 14 2010 - 05:47:40 EST


On Fri, Mar 12, 2010 at 12:46:48PM -0300, Arnaldo Carvalho de Melo wrote:
> From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>
> [root@doppio ~]# perf report -i newt.data | head -10
> # Samples: 11999679868
> #
> # Overhead Command Shared Object Symbol
> # ........ ....... ............................. ......
> #
> 63.61% perf libslang.so.2.1.4 [.] SLsmg_write_chars
> 6.30% perf perf [.] symbols__find
> 2.19% perf libnewt.so.0.52.10 [.] newtListboxAppendEntry
> 2.08% perf libslang.so.2.1.4 [.] SLsmg_write_chars@plt
> 1.99% perf libc-2.10.2.so [.] _IO_vfprintf_internal
> [root@doppio ~]#
>
> Not good, the newt form for report works, but slang has to eat the cost of the
> additional callgraph lines everytime it prints a line, and the callgraph
> doesn't appear on the screen, so move the callgraph printing to a separate
> function and don't use it in newt.c.
>
> Newt tree widgets are being investigated to properly support callgraphs, but
> till that gets merged, lets remove this huge overhead and show at least the
> symbol overheads for a callgraph rich perf.data with good performance.
>
> Cc: Frédéric Weisbecker <fweisbec@xxxxxxxxx>
> Cc: Mike Galbraith <efault@xxxxxx>
> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> Cc: Paul Mackerras <paulus@xxxxxxxxx>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>


Hmm, so for now the callchain won't work anymore until
it gets properly reimplemented right?

Not that much a problem as a necessary step if it really makes
easier for the newt integration.

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