From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from haymarket.ed.ac.uk (haymarket.ed.ac.uk [129.215.128.53]) by kvack.org (8.8.7/8.8.7) with ESMTP id PAA31312 for ; Mon, 27 Jul 1998 15:48:47 -0400 Date: Mon, 27 Jul 1998 11:54:14 +0100 Message-Id: <199807271054.LAA00705@dax.dcs.ed.ac.uk> From: "Stephen C. Tweedie" MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Subject: Re: More info: 2.1.108 page cache performance on low memory In-Reply-To: References: <87ww93dvyt.fsf@atlas.CARNet.hr> Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Zlatko Calusic , "Stephen C. Tweedie" , "Eric W. Biederman" , Linux MM List-ID: Hi, On Fri, 24 Jul 1998 23:55:10 +0200 (CEST), Rik van Riel said: > I admit your patch (multiple aging) should work even better, > but in order to do that, we probably want to make it auto-tuning > on the borrow percentage: > - if page_cache_size > borrow + 5% --> add aging loop wrong answer... > - if loads_of_disk_io and almost thrashing [*] --> remove aging loop Yep, much better. > [*] this thrashing can be measured by testing the cache hit/mis > rate; if it falls below (say) 50% we could consider thrashing. Doing even more rules based on the actual cache size is a bad thing since it is enforcing an arbitrary limit which does not depend on what the system load is right now. Making it adapt to the current load is ALWAYS going to be a better way of doing things. --Stephen -- This is a majordomo managed list. To unsubscribe, send a message with the body 'unsubscribe linux-mm me@address' to: majordomo@kvack.org