From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 26 Mar 2008 10:56:17 -0700 (PDT) From: Christoph Lameter Subject: Re: larger default page sizes... In-Reply-To: <18409.56843.909298.717089@cargo.ozlabs.ibm.com> Message-ID: References: <20080321.145712.198736315.davem@davemloft.net> <20080324.133722.38645342.davem@davemloft.net> <18408.29107.709577.374424@cargo.ozlabs.ibm.com> <87wsnrgg9q.fsf@basil.nowhere.org> <18409.56843.909298.717089@cargo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Paul Mackerras Cc: Andi Kleen , David Miller , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, torvalds@linux-foundation.org List-ID: On Wed, 26 Mar 2008, Paul Mackerras wrote: > So the improvement in the user time is almost all due to the reduced > TLB misses (as one would expect). For the system time, using 64k > pages in the VM reduces it by about 21%, and using 64k hardware pages > reduces it by another 30%. So the reduction in kernel overhead is > significant but not as large as the impact of reducing TLB misses. One should emphasize that this test was a kernel compile which is not a load that gains much from larger pages. 4k pages are mostly okay for loads that use large amounts of small files. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org