From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: Getting big areas of memory, in 2.3.x? Date: Fri, 10 Dec 1999 00:37:55 +0000 (GMT) In-Reply-To: <14416.18872.811910.38578@liveoak.engr.sgi.com> from "William J. Earl" at Dec 9, 99 04:30:48 pm Content-Type: text Message-Id: From: Alan Cox Sender: owner-linux-mm@kvack.org Return-Path: To: "William J. Earl" Cc: alan@lxorguk.ukuu.org.uk, mingo@chiara.csoma.elte.hu, jgarzik@mandrakesoft.com, linux-kernel@vger.rutgers.edu, linux-mm@kvack.org List-ID: > Then too, there is the matter of TLB misses for applications which > visit a lot of data, especially on processors with reasonably large > caches. With 4 KB pages and 64 TLB entries, the TLB cannot map all of > a cache larger than 256 KB. If the cache is, say, 2 MB and the > application cycles through many of the pages in the cache in a loop, > you can wind up with a TLB miss for almost every load (other than those from > the stack). With 1 MB pages, there are almost no TLB misses. With very large amounts of memory I don't doubt this. X86 is alas crippled with a choice of 4K, 2Mb or 4Mb pages. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://humbolt.geo.uu.nl/Linux-MM/