[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: our benchmark-suite

From: Andy Wingo
Subject: Re: our benchmark-suite
Date: Wed, 16 May 2012 19:01:49 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (gnu/linux)


On Wed 25 Apr 2012 22:39, address@hidden (Ludovic Courtès) writes:

>> So, those are the problems: benchmarks running for inappropriate,
>> inconsistent durations;
> I don’t really see such a problem.  It doesn’t matter to me if
> ‘’ takes 2mn while ‘’ takes 40s, since I’m not
> comparing them.

Running a benchmark for 2 minutes is not harmful to the results, but it
is a bit needless.  One second is enough.

However, running a benchmark for just a few milliseconds is not very

;; (" if-<bool>-then: executing then" 330000 real 0.011994627 
real/iteration 3.63473545454545e-8 run/iteration 3.62829060606061e-8 
core/iteration 9.61427360606058e-10 gc 0.0)

That's 12 milliseconds.  The jitter there is too much.

>> inappropriate benchmarks;
> I agree that things like ‘’ are not very relevant now.  But there
> are also appropriate benchmarks, and benchmarks are always better than
> wild guess.  ;-)

Agreed :-)

>> and benchmarks being optimized out.
> That should be fixed.

In what way?  It would make those benchmarks different.

Thesis: anything for which you would want to turn off the optimizer is
not a good benchmark anyway.

See also:

>> My proposal is to rebase the iteration count in to run
>> for 0.5s on some modern machine, and adjust all benchmarks to match,
>> removing those benchmarks that do not measure anything useful.
> Sounds good.  However, adjusting iteration counts of the benchmarks
> themselves should be done rarely, as it breaks performance tracking like
> <>.

I think we've established that this isn't the case -- modulo the effect
that such a change would have on GC (process image size, etc)

>> Finally we should perhaps enable automatic scaling of the iteration
>> count.  What do folks think about that?
>> On the positive side, all of our benchmarks are very clear that they are
>> a time per number of iterations, and so this change should not affect
>> users that measure time per iteration.
> If the reported time is divided by the global iteration count, then
> automatic scaling of the global iteration count would be good, yes.

OK, will do.

Speak now or be surprised by a commit!



reply via email to

[Prev in Thread] Current Thread [Next in Thread]