Date: Tue, 7 Aug 2001 15:55:10 -0400 From: Bosko Milekic <bmilekic@technokratis.com> To: Matt Dillon <dillon@earth.backplane.com> Cc: Terry Lambert <tlambert2@mindspring.com>, Mike Smith <msmith@FreeBSD.ORG>, Zhihui Zhang <zzhang@cs.binghamton.edu>, freebsd-hackers@FreeBSD.ORG Subject: Re: Allocate a page at interrupt time Message-ID: <20010807155510.A50114@technokratis.com> In-Reply-To: <200108071919.f77JJ1d35789@earth.backplane.com>; from dillon@earth.backplane.com on Tue, Aug 07, 2001 at 12:19:01PM -0700 References: <200108070739.f777dmi08218@mass.dis.org> <3B6FB0AE.8D40EF5D@mindspring.com> <200108071655.f77Gt9M32808@earth.backplane.com> <3B703029.2BB6D25A@mindspring.com> <200108071919.f77JJ1d35789@earth.backplane.com>
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On Tue, Aug 07, 2001 at 12:19:01PM -0700, Matt Dillon wrote: > Cache line invalidation does not require an IPI. TLB > shootdowns require IPIs. TLB shootdowns are unrelated to > interrupt threads, they only occur when shared mmu mappings > change. Cache line invalidation can waste cpu cycles -- > when cache mastership changes occur between cpus due to > threads being switched between cpus. I consider this a > serious problem in -current. I don't think it's fair to consider this a serious problem seeing as how, as far as I'm aware, we've intended to eventually introduce code that will favor keeping threads running on one CPU on that same CPU as long as it is reasonable to do so (which should be most of the time). I think after briefly discussing with Alfred on IRC that Alfred has some CPU affinity patches on the way, but I'm not sure if they address thread scheduling with the above intent in mind or if they merely introduce an _interface_ to bind a thread to a single CPU. > -Matt -- Bosko Milekic bmilekic@technokratis.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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