Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964960AbXBLQhW (ORCPT ); Mon, 12 Feb 2007 11:37:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964959AbXBLQhW (ORCPT ); Mon, 12 Feb 2007 11:37:22 -0500 Received: from mpemail.mpe.mpg.de ([130.183.137.110]:34525 "EHLO mpemail.mpe.mpg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964960AbXBLQhV convert rfc822-to-8bit (ORCPT ); Mon, 12 Feb 2007 11:37:21 -0500 From: "Martin A. Fink" Organization: MPE To: linux-kernel@vger.kernel.org Subject: Re: SATA-performance: Linux vs. FreeBSD Date: Mon, 12 Feb 2007 17:37:12 +0100 User-Agent: KMail/1.8 References: <200702121502.17130.fink@mpe.mpg.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200702121737.12882.fink@mpe.mpg.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2384 Lines: 47 Some more info: :~> strace -c -T -o trace.out dd if=/dev/zero of=test.txt bs=10MB count=200 200+0 Datens?tze ein 200+0 Datens?tze aus 2000000000 bytes (2,0 GB) copied, 52,8632 seconds, 37,8 MB/s test.txt: % time seconds usecs/call calls errors syscall ------ ----------- ----------- --------- --------- ---------------- 93.26 6.845265 33555 204 write 6.41 0.470283 11757 40 18 open 0.32 0.023687 116 205 read 0.00 0.000149 9 16 mmap2 0.00 0.000119 40 3 munmap 0.00 0.000081 3 24 close 0.00 0.000068 6 11 old_mmap 0.00 0.000064 3 20 fstat64 0.00 0.000040 4 10 rt_sigaction 0.00 0.000036 12 3 madvise 0.00 0.000014 7 2 clock_gettime 0.00 0.000010 3 3 brk 0.00 0.000008 8 1 _sysctl 0.00 0.000007 7 1 1 access 0.00 0.000006 6 1 mprotect 0.00 0.000005 5 1 futex 0.00 0.000004 4 1 uname 0.00 0.000004 4 1 _llseek 0.00 0.000003 3 1 rt_sigprocmask 0.00 0.000003 3 1 getrlimit 0.00 0.000003 3 1 set_thread_area 0.00 0.000003 3 1 set_tid_address ------ ----------- ----------- --------- --------- ---------------- 100.00 7.339862 551 19 total This means, that the CPU is only 7.3 of 52.8 seconds working. This is what one can hear: If I run programs where the time they need is the same time as strace says, then I have 100% CPU load and the cpu fan starts to blow heavily. In the case here, the heat fan does not do anything. It looks like the SATA driver simply blocks the CPU while doing whatever... - 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/