On Sun, Apr 18, 2010 at 09:22:21PM +0100, Simon Riggs wrote: > On Sun, 2010-04-18 at 13:16 -0700, David Fetter wrote: > > On Sun, Apr 18, 2010 at 12:01:05PM +0100, Simon Riggs wrote: > > > On Sun, 2010-04-18 at 08:24 +0100, Simon Riggs wrote: > > > > On Sat, 2010-04-17 at 18:52 -0400, Tom Lane wrote: > > > > > Simon Riggs <si...@2ndquadrant.com> writes: > > > > > > What I'm not clear on is why you've used a spinlock > > > > > > everywhere when only weak-memory thang CPUs are a problem. > > > > > > Why not have a weak-memory-protect macro that does does > > > > > > nada when the hardware already protects us? (i.e. a > > > > > > spinlock only for the hardware that needs it). > > > > > > > > > > Well, we could certainly consider that, if we had enough > > > > > places where there was a demonstrable benefit from it. I > > > > > couldn't measure any real slowdown from adding a spinlock in > > > > > that sinval code, so I didn't propose doing so at the time > > > > > --- and I'm pretty dubious that this code is sufficiently > > > > > performance-critical to justify the work, either. > > > > > > > > OK, I'll put a spinlock around access to the head of the > > > > array. > > > > > > v2 patch attached > > > > If you've committed this, or any other patch you've sent here, > > *please* mention so on the same thread. > > I haven't yet. I've written two patches - this is a major module > rewrite and is still under discussion. The other patch has nothing > to do with this (though I did accidentally include a couple of > changes from this patch and immediately revoked them). > > I will wait awhile to see if anybody has some independent test > results.
Thanks :) Cheers, David. -- David Fetter <da...@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fet...@gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
