From owner-freebsd-current@FreeBSD.ORG Mon Jan 14 11:00:58 2008 Return-Path: Delivered-To: current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 32FCE16A41B; Mon, 14 Jan 2008 11:00:58 +0000 (UTC) (envelope-from philip@paeps.cx) Received: from gateway.nixsys.be (gateway.nixsys.be [IPv6:2001:6f8:32f::42]) by mx1.freebsd.org (Postfix) with ESMTP id D1D1313C468; Mon, 14 Jan 2008 11:00:57 +0000 (UTC) (envelope-from philip@paeps.cx) Received: from wotan.home.paeps.cx (wotan.home.paeps.cx [IPv6:2001:6f8:32f:10:a00:20ff:fe9b:138c]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "wotan.home.paeps.cx", Issuer "NixSys CA" (verified OK)) by gateway.nixsys.be (Postfix) with ESMTP id F10FE404D; Mon, 14 Jan 2008 12:00:56 +0100 (CET) Received: from fasolt.home.paeps.cx (fasolt.home.paeps.cx [IPv6:2001:6f8:32f:10:214:5eff:feca:2496]) by wotan.home.paeps.cx (Postfix) with ESMTP id 1814661D5; Mon, 14 Jan 2008 12:00:55 +0100 (CET) Received: from fasolt.home.paeps.cx (philip@localhost [127.0.0.1]) by fasolt.home.paeps.cx (8.14.2/8.14.2) with ESMTP id m0EB0s46025208; Mon, 14 Jan 2008 12:00:54 +0100 (CET) (envelope-from philip@fasolt.home.paeps.cx) Received: (from philip@localhost) by fasolt.home.paeps.cx (8.14.2/8.14.2/Submit) id m0EB0sCh025207; Mon, 14 Jan 2008 12:00:54 +0100 (CET) (envelope-from philip) Date: Mon, 14 Jan 2008 12:00:54 +0100 From: Philip Paeps To: Kris Kennaway Message-ID: <20080114110054.GK17508@fasolt.home.paeps.cx> Mail-Followup-To: Kris Kennaway , current@freebsd.org, jls@freebsd.org References: <478A739F.2030003@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <478A739F.2030003@FreeBSD.org> X-PGP-Fingerprint: 356B AE02 4763 F739 2FA2 E438 2649 E628 C5D3 4D05 X-Date: Today is Prickle-Prickle, the 14th day of Chaos in the YOLD 3174 X-Date-in-France: Quintidi 25 =?utf-8?B?Tml2w7Rz?= =?utf-8?Q?e?= CCXVI, jour du chat X-Date-in-Rome: ante diem XIX Kalendas Februarias MMDCCLXI ab Urbe Condida X-Phase-of-Moon: The Moon is Waxing Crescent (36% of Full) X-Message-Flag: Get a proper mailclient! Organization: Happily Disorganized User-Agent: Mutt/1.5.17 (2007-11-01) Cc: jls@FreeBSD.org, current@FreeBSD.org Subject: Re: mpsafe psm driver needed X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Jan 2008 11:00:58 -0000 On 2008-01-13 21:25:03 (+0100), Kris Kennaway wrote: > I've been looking at some mutex profiling traces from users of 6.x and 7.x > who are reporting that their mouse pointer sometimes freezes when their > system is busy. In most of the situations I have looked at this is because > the psm driver is Giant-locked, and competes with other things like the > syncer (in 6.x), or sysctl calls (I have a WIP for this that I need to > revisit). > > This is a minor problem from a grand architectural point of view but an > important one from a usability point of view. I believe these particular > interactivity problems would be resolved if the psm driver no longer > required Giant. Is anyone able to work on this? I have taken a look at this in the past. It's not a trivial problem. There is a lot of what I can only charitably call "legacy code" in psm and it appears that as soon as you touch any of it, it upsets at least one brand of KVM "out there". One of my mentees has been working on a rewrite for a while, but the project has not yet been committed to cvs. jls: any news on this? - Philip -- Philip Paeps Please don't Cc me, I am philip@freebsd.org subscribed to the list. It is impossible for an optimist to be pleasantly suprised.