[webkit-dev] Tip: Use 64-bit git binaries on Mac OS X
jorlow at chromium.org
Thu Dec 9 03:43:52 PST 2010
For what it's worth, on my 12GB of ram mac pro:
$ sudo sysctl -w kern.maxvnodes=384000
kern.maxvnodes: 197632 -> 384000
Took times from 2.11-2.06 down to 2.05-2.02. I.e. it made a small
difference, but not much. The 64 bit patch definitely seemed to help, but I
didn't think to time before and after.
On Wed, Dec 8, 2010 at 11:38 PM, Eric Seidel <eric at webkit.org> wrote:
> Mark Rowe pointed out to me over IRC that the real problem is we're
> blowing out the vnode cache.
> Even on an 8GB machine, the default cache is too small for all of
> WebKit to fit in it.
> On my 4GB machine (and on Mark's 8GB) we tried incrementing the cache
> to 384000 (the 4GB default is 64512 and the 8GB default is 128000).
> My git status times dropped again by over 50% to 2.6 seconds! (still
> an eternity compared to a linux machine of course...)
> If you'd like to play around with this, you can set your vnode cache limit
> sudo sysctl -w kern.maxvnodes=384000
> You can read it with:
> sysctl kern.maxvnodes
> You can test to see if the cache is large enough by trying:
> git status; time git status
> the second one should be very fast if your cache is large enough.
> I don't know what the exact right trade-off is. I believe the vnode
> cache uses wired memory (which is a limited resource!). As far as I
> can tell you can't decrease the cache max w/o rebooting. sysctl will
> set it, but setting it to a smaller number seems to have not effect.
> I don't know how to make the setting last across reboots. Mark
> mentioned that putting the setting in /etc/sysctl.conf should work,
> but that at least for his machine that didn't seem to have any effect
> for this particular setting.
> That's what I know.
> On Wed, Dec 8, 2010 at 3:02 PM, Eric Seidel <eric at webkit.org> wrote:
> > FYI, my git status runs on my Mac Book Pro were an average of 9.2 seconds
> (git version 1.7.1, git-osx-installer) before installing Mihai's 64bit build
> (git version 184.108.40.206), and were 6.0 seconds after.
> > -eric
> > On Wed, Dec 8, 2010 at 2:20 PM, Eric Seidel <eric at webkit.org> wrote:
> >> I've posted a patch to make webkit-patch warn users when they're on a
> 64-bit system with a 32-bit git:
> >> https://bugs.webkit.org/show_bug.cgi?id=50715
> >> 4 seconds on every git status is huge. webkit-patch upload has to run
> at least 3 git status commands (due to expecting files to change on disk
> during operation), so this means a savings of 12 seconds on your machine!
> >> -eric
> >> On Tue, Dec 7, 2010 at 4:04 PM, Mihai Parparita <mihaip at chromium.org>
> >>> After complaining to a Linux-using friend for the n-th time that "git
> >>> status" was much slower on my Snow Leopard machine than on his Linux
> >>> box, I decided to look into why this is. As it turns out, most people
> >>> get git binaries from http://code.google.com/p/git-osx-installer/,
> >>> which are 32-bit. Switching to 64-bit binaries made git status go from
> >>> 6.58s to 2.50s (mainly because this does fewer mmaps).
> >>> You can download a 64-bit binary installer from
> >>> or you can build it yourself (more details at
> >>> Mihai
> >>> _______________________________________________
> >>> webkit-dev mailing list
> >>> webkit-dev at lists.webkit.org
> >>> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
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