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Re: LMbench as gcc performance regression test?
- From: Dan Kegel <dank at kegel dot com>
- To: Daniel Jacobowitz <dan at debian dot org>
- Cc: GCC Mailing List <gcc at gcc dot gnu dot org>, linux-kernel at vger dot kernel dot org
- Date: Sun, 31 Aug 2003 08:59:10 -0700
- Subject: Re: LMbench as gcc performance regression test?
- References: <3F51A201.firstname.lastname@example.org> <20030831152449.GA6893@nevyn.them.org>
Daniel Jacobowitz wrote:
On Sun, Aug 31, 2003 at 12:21:37AM -0700, Dan Kegel wrote:
http://cs.nmu.edu/~benchmark/ has an interesting little graph
of LMBench results vs. Linux kernel version, all done with the
Has anyone seen a similar graph showing LMBench results vs. gcc version,
all done with the same Linux kernel?
And does everyone agree that's a meaningful way to compare the
performance of code generated by different compilers?
It's been a while since I looked at lmbench but: why do you think this
would be useful? It's a system and kernel benchmark; I doubt
optimization makes much difference at all.
I need to make sure that moving to a newer compiler for our kernel
will cause no performance regressions. Before bothering to bring up a
real-world networking application and measuring its performance
under the new compiler, it seems sensible to use a couple microbenchmarks
to verify that identifiable parts of the system have
not degraded in performance.
I myself am quite convinced I need to move to a newer compiler,
since I keep running into problems building various things with
old compilers, but my users are very conservative and skeptical;
I have to build a solid case for updating. Hence the insane amount
of time I spent figuring out and documenting how to build and test
the various versions of gcc and glibc (http://kegel.com/crosstool),
and then understanding the regression test failures.