[FFmpeg-devel] Profiling the library

[Zuxy Meng]

Hi,

2007/5/10, Thorsten Jordan <tjordan at macrosystem.de>:
> Luca Barbato schrieb:
> > Thorsten Jordan wrote:
> >> Hello,
> >>
> > Use valgrind to get a nice callgraph (that could also be visualized in a
> > quite good way by kcachegrind)
> > use oprofile to get performance data for the code (I'd suggest you to
> > check cache miss)
> Thanks for this information, it seems that the alternative gprof can't
> be used anyway, because when i recompile ffmpeg (SVN tarball of 30min
> ago) with my gcc (4.1.3 20070429 (prerelease) (Debian 4.1.2-6)), i get
> this (configure with --enable-gprof):
>
> h264.c: At top level:
> cabac.h:109: warning: 'put_cabac_static' defined but not used
> cabac.h:155: warning: 'put_cabac_terminate' defined but not used
> cabac.h:183: warning: 'put_cabac_u' defined but not used
> cabac.h:218: warning: 'put_cabac_ueg' defined but not used
> cabac.h:270: warning: 'refill2' defined but not used
> cabac.h:808: warning: 'get_cabac_u' defined but not used
> cabac.h:824: warning: 'get_cabac_ueg' defined but not used
> cabac.h: In function 'get_cabac_noinline':
> cabac.h:522: error: can't find a register in class 'GENERAL_REGS' while
> reloading 'asm'
>
> i dont know what the -pg option has to do with assembler register usage,
> but it works without the --enable-gprof in configure.

I guess -pg mandates -fno-omit-frame-pointer, which leaves gcc with no
available registers when compiling cabac.h

-- 
Zuxy
Beauty is truth,
While truth is beauty.
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