On Thu, 2011-07-07 at 17:31 -0700, Geoff Hoffman wrote:
Tony -
Strange results to be sure. You probably thought of all this, but...
Did you check Memcached is working correctly without Subversion?
Did you check the results of checking out or updating the 2nd or 3rd
time?
In other words, it may take longer the first time because every object
in the repo has to be checked for existence/expiry in the cache.
Did you check that you gave Memcached enough memory to fit the entire
250mb repo (comfortably) in RAM?
If not then memcached itself tries to use swap space?
32-bit or 64-bit VM?
As before, PAE kernel. Processor claims to be a Xeon. Not sure how to tell what
the underlying VM software is doing.
I ran my test with memcached -m 512
That is, 512M memory. Checkout completed in 11 minutes - better than before,
but still slower than without memcached.
memcached-tool localhost stats reports
get_hits 481964
get_misses 71527
among many other things, so the cache is certainly working (numbers were much
smaller before the checkout).
Running again completed in 8m 34s, still too slow...
Tony
Did you try it on physical hardware?
On Thu, Jul 7, 2011 at 4:59 PM, Daniel Shahaf <[email protected]>
wrote:
This doesn't address memcached directly, but there has been a
/lot/ of
work on server-side optimization and caching in 1.7 (also for
non-memcached-backed caches).
http://subversion.apache.org/docs/release-notes/1.7#server-performance-tuning
You might want to take 1.7.0-alpha3 for a spin...
Tony Butt wrote on Wed, Jul 06, 2011 at 15:20:27 +1000:
> We are running subversion 1.6.17 on a vmware hosted server.
We recently
> reconfigured the server to give 4 virtual CPUs (up from 1),
and a
> significant amount of memory.
>
>
> In order to spruce up our performance a little, I looked into
the use of
> memcached with subversion again, found the correct config
parameter, and
> set it up. Our server is running Ubuntu 10.04, Apache 2.2.
Access
> mechanism is http (of course). The client used is running
Ubuntu 11.04,
> and svn commandline (1.6.17 also)
>
> The results were interesting, to say the least.
>
> Checkout of a tree, about 250M in size:
>
> Without memcached, 1 1/2 to 2 minutes, varies with server load
> With memcached, 12 minutes (!)
>
> Update of the same tree,
> Without memcached, 9 seconds
> With memcached, 14 seconds - repeated several times, similar
results.
>
> I am not sure what anyone else's experience is, but we will
not be
> enabling memcached for subversion any time soon.
> --
> Tony Butt <[email protected]>
> CEA Technologies
>
--
Tony Butt <[email protected]>
CEA Technologies
