Date: Wed, 17 Jul 2002 13:36:40 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Luigi Rizzo <rizzo@icir.org> Cc: arch@freebsd.org Subject: RE: proposed changes to kern_switch.c and kern_synch.c Message-ID: <XFMail.20020717133640.jhb@FreeBSD.org> In-Reply-To: <20020716235216.B6785@iguana.icir.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 17-Jul-2002 Luigi Rizzo wrote: > Hi, > we have implemented a weight-based process scheduler > for FreeBSD-stable, and are trying to port it to -current (in the > description below replace "process" with "thread/kse" as appropriate > for the -current case). Unfortunately, the differences between -current and -stable in this area aren't that simple. I think while developing on this on -stable is fine, trying to retrofit those changes into -current will be fairly hard. Mostly because you basically need to rewrite a lot of it. The current scheduler is still very much a work in progress and I think we need to not try to do too many things at once. Some remaining issues that I think need to be done first before we look into this: - Finish up KSE changes - Really make the scheduler fully preemptive - Get rid of schedcpu() in favor of event-driven priority updates somewhat similar to SVR4 as described in Unix Internals - A few other simplifications would be to have things like turnstiles and generic sleep queues shared between at least cv's and sleep/wakeup, possibly with turnstiles as well. Some other notes: I think kern_switch.c should just contain the code to support processor runqueues and possibly mi_switch(). > 3. implement a function which, under control of a sysctl call, > activate a new scheduler (by initialising all the function > pointers to appropriate values) and moves all processes from > the old to the new one. In SVR4 different processes could be in different scheduling classes that could cooperate with each other. I think that is a better long-term design goal then requiring switch-overs. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?XFMail.20020717133640.jhb>