problem with mips-linux gprof

problem with mips-linux gprof

[Krishna]

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Hi,
   
  I have been trying to use mips-linux gprof from last few days. But not able to get profile data. Here what I did: 
   
  1. cross compiled program for mips-linux as follows
  $ mips-unknown-linux-gnu-gcc -o hello hello.c -g -pg -lc
   
  2. then ran hello on target mips-linux system (BCM91480B) which generates gmon.out file.
   
  3. copy gmon.out to the host.
   
  4. run mips-linux gprof as follows 
  $mips-unknown-linux-gnu-gprof hello
   
  But i get the following error message
  mips-unknown-linux-gnu-gprof: gmon.out file is missing call-graph data
   
  Then I googled around and found someone suggesting to use lib_p.a during compilation. But i don't have that library.
  Please someone help me to get rid of this problem.
   
  Thanks and Regards,
  Krishna

			
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Re: problem with mips-linux gprof

[James E Wilson]

On Thu, 2006-04-27 at 23:37, Krishna wrote:
> But i get the following error message
> mips-unknown-linux-gnu-gprof: gmon.out file is missing call-graph data

Add a second function to your testcase.  You have to have at least two
functions in order to have a call graph.

If your testcase has only one function, main, then there will be no
useful call graph info, so the -pg library support won't bother to emit
one, and then gprof complains that it is missing.  This is correct, but
not very useful, and perhaps should be considered a bug.  I think gprof
should just default to emitting a flat profile in this case, without
giving an error, so I'd call this a binutils bug.

In the absence of call-graph info, you can use the gprof -p option to
get a flat profile.

The above assumes you don't have a profiled C library available.  If you
did, then you would have at least two profiled functions, main and
printf, and would have gotten some call graph info emitted.  If you
don't have a profiled C library available, you could try compiling one
yourself.  There is a glibc configure option --enable-profile for that. 
I've never tried this myself.  I'd expect this to be a non-trivial
exercise.  Besides the issue of compiling glibc, you also need to
install the profiled library, and arrange to link with it.
-- 
Jim Wilson, GNU Tools Support, http://www.specifix.com

Re: problem with mips-linux gprof

[Daniel Jacobowitz]

On Fri, Apr 28, 2006 at 12:52:07PM -0700, James E Wilson wrote:
> The above assumes you don't have a profiled C library available.  If you
> did, then you would have at least two profiled functions, main and
> printf, and would have gotten some call graph info emitted.  If you
> don't have a profiled C library available, you could try compiling one
> yourself.  There is a glibc configure option --enable-profile for that. 
> I've never tried this myself.  I'd expect this to be a non-trivial
> exercise.  Besides the issue of compiling glibc, you also need to
> install the profiled library, and arrange to link with it.

Many prebuilt distributions already ship it; FWIW, if you link with
"-profile" instead of "-pg", GCC will automatically attempt to use
-lc_p.

-- 
Daniel Jacobowitz
CodeSourcery