Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261560AbVB1FN5 (ORCPT ); Mon, 28 Feb 2005 00:13:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261561AbVB1FN4 (ORCPT ); Mon, 28 Feb 2005 00:13:56 -0500 Received: from smtp201.mail.sc5.yahoo.com ([216.136.129.91]:39855 "HELO smtp201.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261560AbVB1FNt (ORCPT ); Mon, 28 Feb 2005 00:13:49 -0500 Message-ID: <4222A887.80301@yahoo.com.au> Date: Mon, 28 Feb 2005 16:13:43 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20050105 Debian/1.7.5-1 X-Accept-Language: en MIME-Version: 1.0 To: Christian Schmid CC: Rik van Riel , linux-kernel@vger.kernel.org Subject: Re: Slowdown on high-load machines with 3000 sockets References: <4221FB13.6090908@rapidforum.com> <422239A8.1090503@rapidforum.com> <42225B34.7020104@rapidforum.com> <42226607.6020803@rapidforum.com> In-Reply-To: <42226607.6020803@rapidforum.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 938 Lines: 26 Christian Schmid wrote: > I already tried with 300 KB and even used a perl-hash as a horrible-slow > buffer for a readahead-replacement. It still slowed down on the syswrite > to the socket. Thats the strange thing. > Do you have to use manual readahead though? What is the performance like if you just let the kernel do its own thing? The kernel's readahead provides things like automatic scaling and thrashing control, so if possible you should just stick to that. Although you may want to experiment with the maximum readahead on your working disks: /sys/block/???/queue/read_ahead_kb Also, can we get a testcase (ie. minimal compilable code) to reproduce this problem? Thanks, Nick - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/