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Re: svntest and tmpfs slow as disk

From: Blair Zajac <blair_at_orcaware.com>
Date: 2004-02-17 21:50:35 CET

Philip Martin wrote:
> Blair Zajac <blair@orcaware.com> writes:
> > I'm now running svntest on a dual 3.06 Ghz system with 2 Gbytes of
> > RAM and using the ramdisk, but it's just as fast as running
> > the tests to disk.
> Have the physical times got better, or the tmpfs times got worse?

I don't have any old systems to compare this with, as this is my
first install of svntest.

> > Has anybody else seen this.
> No, I see tmpfs as significantly faster. Running update_tests.py on
> an old dual P3 I see the physical disk take about 230s and the tmpfs
> disk about 120s. That's wall clock time, both use about 60s of CPU.
> The figures are much the same for ra_local and ra_svn, while ra_dav
> takes about 10s more wall clock time.
> One of the limiting factors is the command line client's timestamp
> sleep; that's why the wall clock time is always going to be
> significantly greater than the CPU time. On the other hand I can use
> different build directories to run different RA layers in parallel

I was thinking about this and maybe the identical wall clock times
for ram vs ext3 filesystem performance is that the ext3 filesystem
is on a battery backed RAID filesystem which lets the OS think that
writes happen immediately??? So maybe on a normal filesystem without
the immediate writes I would see similar time differences as other

Regarding the different build directories, do you have all three
builds proceeding from the building apr/apr-util/httpd/svn and
running make test, or just the make test bit? What changes did
you make to svntest.sh?


Blair Zajac <blair@orcaware.com>
Plots of your system's performance - http://www.orcaware.com/orca/
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Received on Tue Feb 17 21:50:53 2004

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