[maemo-developers] oprofile on ARM

[From: Felipe Contreras]

On Sun, Apr 11, 2010 at 10:46 AM, Alberto Mardegan
<mardy at users.sourceforge.net> wrote:
>  again I've tried to profile Mapper on the N900, with no results. First I
> tried gprof, but it gives me all 0.0 times (and a google search reveals that
> this is a common problem in maemo, even though I didn't find an explanation
> of it); then I tried oprofile, which gives me an output like this:
>
> ==========
> samples  %        image name               symbol name
> 3007     38.3497  no-vmlinux               /no-vmlinux
> 1083     13.8120  libclutter-eglx-1.0.so.0.8.0
> /usr/lib/libclutter-eglx-1.0.so.0.8.0
> 424       5.4075  libc-2.5.so              memcpy
> 336       4.2852  libpng12.so.0.37.0       png_do_expand_palette
> 317       4.0429  libz.so.1.2.3            /usr/lib/libz.so.1.2.3
> 286       3.6475  libGLESv2.so             /usr/lib/libGLESv2.so
> 219       2.7930  ld-2.5.so                do_lookup_x
> 120       1.5304  libglslcompiler.so       /usr/lib/libglslcompiler.so
> 55        0.7014  libc-2.5.so              _int_malloc
> 48        0.6122  libpthread-2.5.so        pthread_mutex_lock
> 44        0.5612  libpixman-1.so.0.15.3    fbCompositeSolidMask_nx8x8888neon
> 36        0.4591  libsrv_um.so             /usr/lib/libsrv_um.so
> 35        0.4464  libc-2.5.so              malloc
> 35        0.4464  libsqlite3.so.0.8.6      /usr/lib/libsqlite3.so.0.8.6
> 34        0.4336  libc-2.5.so              memset
> 34        0.4336  libglib-2.0.so.0.2000.3  g_slice_alloc
> 32        0.4081  libglib-2.0.so.0.2000.3  g_hash_table_lookup
> [...]
> ==========
> (I got this output after moving the oprofile collected data into Scratchbox)
>
> But this doesn't help me, as Mapper's own functions appear on the bottom of
> the list and seem to take very little time. I tried to use the "-c" option
> of opreport to see the call graph, but it doesn't seem to be working
> properly, as for every function it gives this output:
>
> ==========
> -------------------------------------------------------------------------------
> 336       4.2852  libpng12.so.0.37.0       png_do_expand_palette
>  336      100.000  libpng12.so.0.37.0       png_do_expand_palette [self]
> -------------------------------------------------------------------------------
> ==========
>
> It seems it cannot resolve the caller, why?

Did you try to reinitialize OProfile?

> One more question: how can I see the total time taken by a function? I would
> expect to see the main() function of Mapper at the top of the list, as it's
> clearly the function that takes most time, but it doesn't even appear in the
> list at all.
> So I assume that these times are net (that is, the time spend in subroutines
> is excluded from the function times), which might be useful in some case,
> but it definitely prevents me from knowing what functions in Mapper need to
> be optimized...

I use Gprof2Dot for that:
http://wiki.jrfonseca.googlecode.com/hg/gprof2dot.png

I just added some basic information for this here:
http://elinux.org/OProfile

Cheers.

-- 
Felipe Contreras