Date: Wed, 24 Nov 1999 21:25:21 -0800 From: Jason Evans <jasone@canonware.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: freebsd-arch@freebsd.org Subject: Re: Threads Message-ID: <19991124212521.W301@sturm.canonware.com> In-Reply-To: <199911241941.LAA20231@apollo.backplane.com>; from dillon@apollo.backplane.com on Wed, Nov 24, 1999 at 11:41:41AM -0800 References: <Pine.SUN.3.91.991124134533.26314A-100000@pcnet1.pcnet.com> <199911241905.LAA20045@apollo.backplane.com> <14396.15070.190669.25400@avalon.east> <199911241941.LAA20231@apollo.backplane.com>
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On Wed, Nov 24, 1999 at 11:41:41AM -0800, Matthew Dillon wrote: > > :It would be nice to keep an eye out for the future... SMP > :coscheduling of threads. I'd like to see FreeBSD become the OS of the > :fastest computer in the world. Making it easy to coschedule threads > :(or processes for that matter) would go a long way towards displacing > :Linux in this category. > > Coscheduling is a fairly simple mechanism to implement. No real special > cases need to be added to the scheduler itself, you simply ensure that it > is 'most likely' for the threads to be scheduled together by placing them > next to each other in the run queue. > > For example, if you have a single scheduling queue (which I really think > is what we want) and the scheduler on each cpu picks off the next ready > thread from the same queue, and two threads wakeup simultaniously, > you can construct the queueing code such that it is highly likely that > the two threads will each be (nearly) simultaniously assigned a different > cpu and be able to run in parallel. Until reading about DEC's threading efforts (http://www.digital.com/info/DTJF03/DTJF03SC.TXT) a few days ago, I would have agreed with you. However, that paper makes some very valid arguments for needing multiple scheduling queues. The paper is very worthwhile reading. Jason To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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