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 RAA28438 for ; Thu, 25 Jun 1998 17:10:13 -0400 Date: Thu, 25 Jun 1998 22:08:39 +0100 Message-Id: <199806252108.WAA16230@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: Memory management. (fwd) In-Reply-To: References: Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Linux MM List-ID: Hi, On Thu, 25 Jun 1998 18:00:15 +0200 (CEST), Rik van Riel said: > From: Stefane Fermigier > To: H.H.vanRiel@phys.uu.nl > Subject: Memory management. > He said that under most circumstances, Linux was able to get the best > results, but that when huge amounts of data were to be transfered from and > then to disk during the computations, performances were dropping badly. > This would appear when the size of the files that are manipulated > is _half_ of the RAM of the systems, when one would think that RAM > just (approximately) _equal_ to the size of the files would be enough. > According to Remy Card, this might be a question of ``double buffering'', > that is, the data would go to _two_ different RAM buffers instead of just > one. That's right --- it's the old problem of buffering writes through the buffer cache and reads through the page cache. Do you want me to reply to this to say we know about it? --Stephen