Date: Thu, 21 Feb 2002 11:19:15 +1030 From: Greg Lehey <grog@FreeBSD.org> To: Jake Burkholder <jake@locore.ca> Cc: Matthew Dillon <dillon@apollo.backplane.com>, David O'Brien <obrien@FreeBSD.ORG>, current@FreeBSD.ORG Subject: Re: Patch to improve mutex collision performance Message-ID: <20020221111915.N65817@wantadilla.lemis.com> In-Reply-To: <20020218153807.E96115@locore.ca> References: <200202181912.g1IJCGK32122@apollo.backplane.com> <20020218114326.A98974@dragon.nuxi.com> <200202181951.g1IJpip33604@apollo.backplane.com> <20020218153807.E96115@locore.ca>
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On Monday, 18 February 2002 at 15:38:07 -0500, Jake Burkholder wrote: > Apparently, On Mon, Feb 18, 2002 at 11:51:44AM -0800, > Matthew Dillon said words to the effect of; >> I'm fairly sure JHB does not have a patch to address this but, please, >> be my guest and check P4. > > Actually he does. Maybe you should have checked p4 first yourself. Well, maybe, like me, he doesn't know how. I only recently learnt of the existence of this repo, and I still don't know where it is. It certainly wasn't announced on the SMP mailing list. I've seen a few references to p4 there, but no indication of how to access the repo. > What John's patch does is spin while the lock owner is running on > another cpu. Spinning while there are no other processes on the run > queues as well makes sense but you'll also be doing a lot of > acquires and releases of sched_lock. I must be misinterpreting this statement. Under what circumstances do you spin? Yes, I read the "while the owner is running in another CPU", but the way I read that, it turns the blocking lock into a spin lock. Greg -- See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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