Date: Mon, 30 Mar 2009 05:22:20 +1100 From: Peter Jeremy <peterjeremy@optushome.com.au> To: David Xu <davidxu@freebsd.org> Cc: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org, prashant.vaibhav@gmail.com Subject: Re: Improving the kernel/i386 timecounter performance (GSoC proposal) Message-ID: <20090329182219.GC38985@server.vk2pj.dyndns.org> In-Reply-To: <49CEC261.4010803@freebsd.org> References: <11609492.9579.1238167614335.JavaMail.root@vms070.mailsrvcs.net> <49CD0405.1060704@samsco.org> <49CD30E9.7030501@elischer.org> <49CEC261.4010803@freebsd.org>
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[-- Attachment #1 --] On 2009-Mar-29 08:35:45 +0800, David Xu <davidxu@freebsd.org> wrote: >Julian Elischer wrote: >> interestingly it is even feasible to have a per-thread page.. >> it requires that the scheduler change a page table entry tough. > >I will knock his door at midnight if he added such a heavy weight >task in the scheduler, TLB shutdown is horrible, and big code size >squeezing out data from CPU cache is not idea model. >scheduler should be as simple as just a context switching routine. If the TSC is not consistent between all cores (which is probably the most common situation at present), then using the TSC implies knowing which core you are executing on. From a userland perspective, the easiest way to do this is to have a page of data that varies depending on which core you are executing on. -- Peter Jeremy [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.10 (FreeBSD) iEYEARECAAYFAknPvFsACgkQ/opHv/APuIeXKgCgviRrpnxRZFKKu/OZ8Q8LAt7d mOgAoIukrhlHkgJJmLZQMlFRBBO7yzbM =I94l -----END PGP SIGNATURE-----help
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