1.7 timing tests: update great, checkout needs work, upgrade horrible

I'm working with a client and they have a large source source code checkout that
takes over 10 minutes do to an svn update. Their 1.6.x working copy size is 3.6
GB with 74,000 files and 19,230 directories. The amount of IO to do all the
locking and reading entries files is taking a significant amount of time.

They are looking at techniques to speed up updates, as it's a significant
productivity drain, but it's much slower than git-svn.

So we thought we'd try the 1.7 client at r1042760.

The good news is that "svn update" is significantly faster than 1.6, dropping
from over 10 minutes to 3:07 with a cold cache and 0:48 with a warm cache. This
is great.

Unfortunately, it looks like checkout times have gotten worse. On a SATA disk
with ext3:

        Clock System User
        time time time

1.6 5:41 94.1 58.9
1.7 12:20 106.2 99.9

I noticed that doing an strace of the checkout leads to a 1.3 GB file with 1.6.x
and 4.1 GB with 1.7.x, so many more operations.

I haven't been following 1.7 performance lately, but are we aware of this? Are
there any obvious performance fixes here?

I realize that 1.7 is a ways away, but the scalability svn update brings to svn
checkouts is a significant win.

We also tried an 1.6.x checkout followed by a 1.7 upgrade. Last I looked the
process it had 110 minutes of CPU time. Definitely not worth upgrading, faster
to do a fresh checkout, even with the checkout performance slower than 1.6.x.

Blair
Received on 2010-12-07 05:02:40 CET