[darcs-users] darcs benchmarking

[Nathan Gray]

On Tue, Dec 30, 2008 at 10:34:45PM +0100, Petr Rockai wrote:
> Nathan Gray <kolibrie at graystudios.org> writes:
> [snip]
> > It is important to me to be able to benchmark current darcs against
> > the version of darcs we are using in production, so I will know when I
> > can upgrade.

> You need to use a repository that's in darcs1 format for that, and also make
> sure the initialise.sh script doesn't convert them to hashed when creating the
> playgrounds (it uses the system darcs, keeping defaults).

Ah yes.  I must have gotten muddled.

> > Memory usage is interesting.  What darcs-benchmark reports for memory usage
> > does not seem accurate.
> >
> > During the benchmark, in another window, I had a loop running to log
> > stats about darcs processes every 60 seconds:
> >
> >   while [ 1 ]; do ps axo pid,euser,pri,ni,vsize,rssize,s,%cpu,%mem,cputime,etime,comm,args |grep darcs >> process_stats_all.txt; sleep 60; done
> >
> > So while darcs-benchmark reports that it took darcs 2.0.2 1219.6 seconds
> > to check my cap2 repository (which seems fairly accurate), it also
> > reports that it used 288MB (which seems quite a bit less than what was
> > actually used):

> Hm, the 288M figure comes from GHC RTS and is the peak heap size. There's
> additional stuff in the running darcs image, but I'm not sure it could account
> for the 300M difference. *But* if you are using uncompressed patches, it could
> very well be just mmap memory: it gets counted into the memory use of a
> process, even if it's just a mapped file (and behaves more like filesystem
> cache than like actual allocated memory), IIRC.

I did not uncompress them, so am supposing they are compressed
patches in the playpen.

> > -- check, repo = big-zoo/cap2, bin = darcs211...
> > iteration: 1..error: user error (darcs failed with error code 1
> > saying: /home/kolibrie/bin/darcs211 check --no-test +RTS -sstderr 
> > Repairing patch 51/26411 : Fri Jan  1 00:36:41 EST 1999  cvs
> > [snip]
> > Writing pristine 4/42
> > [snip]
> > Writing pristine 21990/22004
> > cleaning up... 33/75 : whxdata
> > [snip]
> > cleaning up... 2787/2906 : LinkInputList
> > darcs211: out of memory (requested 1048576 bytes)
> > )

> Hm, not sure what is in 2.1.1, so can't comment.

That is:

  2.1.1rc2 (+ 281 patches)

> > Benchmarking darcs 2.2.0 got up to about 3GB in about three hours, then
> > hung for several days until I got back from vacation:

> Hm, there's no 2.2.0 yet -- have you used http://darcs.net/ (and from which
> date) or 2.2.0pre1? I have fixed a severe memory leak in 2.2, after the pre1
> release -- if your 2.2 doesn't have my fix for check/repair, it obviously won't
> finish on your big repo with just 4G of RAM.

My 2.2.0 is:

  2.2.0pre1 (prerelease 1)

> To circumvent the hangs, you should probably set some reasonable ulimit. If
> that doesn't help, it's alwas possible just to kill the darcs process being
> benchmarked, the benchmark will continue where it left off.
> 
> If it's at all possible, please grab http://repos.mornfall.net/darcs/branch-2.2
> -- this is what will become 2.2.0pre2 on 3rd January bar any release-critical
> issues pop up in the meantime. It contains the leak fix mentioned above, so it
> should improve check and repair performance drastically. If it doesn't, then we
> have a some bug in there...

Will fetch that version of darcs and benchmark against it, reporting
back here with results.

-kolibrie