Date: Fri, 12 Jul 2002 15:55:16 -0500 From: Alan Cox <alc@cs.rice.edu> To: Matt Dillon <dillon@FreeBSD.org> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern kern_synch.c src/sys/sys proc.h src/sys/vm vm_zeroidle.c src/sys/i386/i386 genassym.c pmap.c Message-ID: <20020712205516.GD5265@cs.rice.edu> In-Reply-To: <200207122017.g6CKH7fx096339@freefall.freebsd.org> References: <200207122017.g6CKH7fx096339@freefall.freebsd.org>
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On Fri, Jul 12, 2002 at 01:17:07PM -0700, Matt Dillon wrote: > dillon 2002/07/12 13:17:07 PDT > > Modified files: > sys/kern kern_synch.c > sys/sys proc.h > sys/vm vm_zeroidle.c > sys/i386/i386 genassym.c pmap.c > Log: > Re-enable the idle page-zeroing code. Remove all IPIs from the idle > page-zeroing code as well as from the general page-zeroing code and use a > lazy tlb page invalidation scheme based on a callback made at the end > of mi_switch. > I think we should try to take this a step further. Specifically, we should recognize when processors are running in user mode in order to avoid IPIs on kernel pmap changes. On reentry to the kernel, the processor would then do whatever is necessary to resync. If too many kernel pmap changes accumulate, then you force a single IPI that performs the changes in bulk. As a start, it would be interesting to know how many IPIs could be avoided by such a scheme. Alan To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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