Date: Mon, 14 Jan 2008 09:20:11 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: jls@freebsd.org, current@freebsd.org Subject: Re: mpsafe psm driver needed Message-ID: <200801140920.12890.jhb@freebsd.org> In-Reply-To: <20080114110054.GK17508@fasolt.home.paeps.cx> References: <478A739F.2030003@FreeBSD.org> <20080114110054.GK17508@fasolt.home.paeps.cx>
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On Monday 14 January 2008 06:00:54 am Philip Paeps wrote: > On 2008-01-13 21:25:03 (+0100), Kris Kennaway <kris@FreeBSD.org> 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? Does psm(4) interface with any subsystems like tty(4)? -- John Baldwin
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