From owner-freebsd-current Wed Feb 20 16:49:24 2002 Delivered-To: freebsd-current@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id 2365737B417; Wed, 20 Feb 2002 16:49:18 -0800 (PST) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id 1A9B17830E; Thu, 21 Feb 2002 11:19:15 +1030 (CST) Date: Thu, 21 Feb 2002 11:19:15 +1030 From: Greg Lehey To: Jake Burkholder Cc: Matthew Dillon , David O'Brien , current@FreeBSD.ORG Subject: Re: Patch to improve mutex collision performance Message-ID: <20020221111915.N65817@wantadilla.lemis.com> References: <200202181912.g1IJCGK32122@apollo.backplane.com> <20020218114326.A98974@dragon.nuxi.com> <200202181951.g1IJpip33604@apollo.backplane.com> <20020218153807.E96115@locore.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20020218153807.E96115@locore.ca> User-Agent: Mutt/1.3.23i Organization: The FreeBSD Project Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG 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