Re: gprof --line taking _forever_

[Ian Lance Taylor]

"David Mathog" <address@hidden> writes:

> > > However, when I try this:
> > > 
> > >  grpof --line /usr/common/ncbi_new/ncbi/build/blastall
> > > 
> > > the CPU pegs at 99% and stays there for at least 45 minutes
> > > (it's still running as I write this.)
> > 
> > You didn't mention which version of the binutils you are using.  Also
> > relevant is type of debugging information--stabs or DWARF.
> 
> Beats me, whatever version 3.3.3 of gcc emits by default with
> the command line options -g -pg on a RedHat 7.3 system.

You can tell by running objdump -h on the binary.  If you see .stab
and .stabstr it is stabs.  If you see .debug_info it is DWARF.

> > gprof --line is known to be slow.  There have been various recent
> > efforts to speed it up by caching more information.  The speedups have
> > been fairly dramatic in some cases.  You may want to try a newer
> > version of the binutils to see if it helps.
> 
> The old version was 2.11.93.0.2 and it ran somewhere between
> 70 and 80 minutes (I didn't time it exactly.)  Following your
> advice I tried gprof 2.14 and used "time" on that one - it ran in
> 74m59s. So the newer version doesn't seem to be much (if any) better
> than the old one in terms of speed with --line.  I also attempted
> to restrict gprof to the function where the most time was spent
> with:
> 
>  gprof --line --time=BlastWordFinder_mh_contig
> 
> but that still ran in 74m19s.

Hmmm.  Sorry for the wasted time.

I would appreciate it if you could file a PR at
http://sources.redhat.com/bugzilla/

Thanks.

Ian