Re: [PATCHv2 00/14] perf diff: Factor diff command

From: Andi Kleen
Date: Wed Oct 03 2012 - 12:21:29 EST


On Wed, Oct 03, 2012 at 06:47:57AM -0700, Arnaldo Carvalho de Melo wrote:
> Em Tue, Oct 02, 2012 at 06:30:02PM +0200, Andi Kleen escreveu:
> > The other problem I ran into is that perf archive doesn't seem to work very
> > well with kernels, so it's hard to move profiles from different kernels
> > around to diff them (e.g. for a performance regression) One way around this
> > would be options to diff to specify the vmlinux etc. manually
>
> Can you describe more precisely what is not working well with 'archive'
> and build ids?

It doesn't write anything to anywhere for me

It also breaks with different perf binaries because it seems to just
do system("perf ...") at some point. This may be related to this.

And synching .cache is a quite clumpsy way even if it worked.

% strace -f -e open -o log perf archive
% grep WR log
20041 open("/dev/tty", O_RDWR|O_NONBLOCK) = 3
20042 open("/tmp/perf-archive-buildids.5uDTJ2", O_RDWR|O_CREAT|O_EXCL, 0600) = 3
20044 open("/tmp/perf-archive-buildids.5uDTJ2", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 3
20045 open("/tmp/perf-archive-manifest.jRy7nP", O_RDWR|O_CREAT|O_EXCL, 0600) = 3
20047 open("/tmp/perf-archive-manifest.jRy7nP", O_WRONLY|O_CREAT|O_APPEND, 0666) = 3
20047 open("/tmp/perf-archive-manifest.jRy7nP", O_WRONLY|O_CREAT|O_APPEND, 0666) = 3
20047 open("/tmp/perf-archive-manifest.jRy7nP", O_WRONLY|O_CREAT|O_APPEND, 0666) = 3
20047 open("/tmp/perf-archive-manifest.jRy7nP", O_WRONLY|O_CREAT|O_APPEND, 0666) = 3
%

-Andi
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