[svn.haxx.se] · SVN Dev · SVN Users · SVN Org · TSVN Dev · TSVN Users · Subclipse Dev · Subclipse Users · this month's index

RE: svn edit

From: Harvey, Edward <Edward.Harvey_at_patni.com>
Date: Tue, 28 Oct 2008 13:09:04 -0400

Incase anybody wants to benchmark anything - on Linux - I learned this from Linus.
     echo 3 >/proc/sys/vm/drop_caches
     http://marc.info/?l=git&m=122487091128096&w=2
     This will make your cache cold, so you can repeat a test with accurate results. (without rebooting)

________________________________________
From: Harvey, Edward
Sent: Tuesday, October 28, 2008 12:49 PM
To: Branko Čibej; dev_at_subversion.tigris.org
Subject: RE: svn edit

> Just to illustrate what I mean by "optimizing WC scans" and put some
> code where my mouth is ... here's a *very* trivial example. See the
> attached script. On my box, the less_stupid scan is consistenly 30-40%
> faster (with full caches!) than the stupid one, merely because it tries
> to keep accesses slightly more local.

I'm not sure what you mean by "with full caches" or "keep access more local" but I do know this -
        I created a similar python script to walk a tree.
        With cold cache, local disk, python walking the tree on 100,000 files takes approx 10 sec
        With cold cache, local disk, "svn stat" on 17,000 files (50,000 including .svn dirs) takes approx 4 mins
        With cold cache, local disk, "git status" on 17,000 files (30,000 including .git dirs) takes approx 2 mins
        Perforce is able to do this is zero time. (a few ms)

Now - If svn is able to get anywhere near the 10 sec mark for 100,000 files, I say fine. But I seriously doubt svn will beat the performance of git by using the same strategy that git uses (walk the tree). This costs at least one order of magnitude in performance.

Put simply, as far as performance is concerned, Perforce has a strategy that beats the pants off either svn or git. Because perforce doesn't need to walk the tree.

This e-mail message may contain proprietary, confidential or legally privileged information for the sole use of the person or entity to whom this message was originally addressed. Any review, e-transmission dissemination or other use of or taking of any action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error kindly delete this e-mail from your records. If it appears that this mail has been forwarded to you without proper authority, please notify us immediately at netadmin_at_patni.com and delete this mail.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe_at_subversion.tigris.org
For additional commands, e-mail: dev-help_at_subversion.tigris.org
Received on 2008-10-28 18:12:09 CET

This is an archived mail posted to the Subversion Dev mailing list.

This site is subject to the Apache Privacy Policy and the Apache Public Forum Archive Policy.