From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762133AbYD2NKw (ORCPT ); Tue, 29 Apr 2008 09:10:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754182AbYD2NKn (ORCPT ); Tue, 29 Apr 2008 09:10:43 -0400 Received: from smtp-out.google.com ([216.239.33.17]:21954 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751847AbYD2NKn (ORCPT ); Tue, 29 Apr 2008 09:10:43 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=received:message-id:date:from:to:subject:mime-version: content-type:content-transfer-encoding:content-disposition; b=xIdja59NCwwPtltQGe1BLwIa96wZ0sonsdnCuWSUPcfgLv6BonQK3upOYWGWYQxLJ jgloFvPq9d+2gweggMxHg== Message-ID: Date: Tue, 29 Apr 2008 09:10:36 -0400 From: "Ross Biro" To: linux-mm@kvack.org, lkml Subject: Page Faults slower in 2.6.25-rc9 than 2.6.23 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I don't know if this has been noticed before. I was benchmarking my page table relocation code and I noticed that on 2.6.25-rc9 page faults take 10% more time than on 2.6.22. This is using lmbench running on an intel x86_64 system. The good news is that the page table relocation code now only adds a 1.6% slow down to page faults. Ross 2.6.25-rc9: File & VM system latencies in microseconds - smaller is better ------------------------------------------------------------------------------- Host OS 0K File 10K File Mmap Prot Page 100fd Create Delete Create Delete Latency Fault Fault selct --------- ------------- ------ ------ ------ ------ ------- ----- ------- ----- ipnn2 Linux 2.6.25- 13.9 7.6111 103.4 9.7453 926.0 0.711 2.14250 2.552 ipnn2 Linux 2.6.25- 13.7 7.6243 310.7 9.6574 932.0 0.750 2.15970 2.555 ipnn2 Linux 2.6.25- 13.9 7.6831 192.5 10.0 927.0 0.760 2.21310 2.553 ipnn2 Linux 2.6.25- 13.9 7.5739 98.4 9.5330 927.0 0.703 2.17610 2.554 ipnn2 Linux 2.6.25- 14.6 7.6429 39.1 10.8 935.0 0.763 2.17250 2.552 ipnn2 Linux 2.6.25- 14.1 7.8777 129.8 9.9375 930.0 0.782 2.26460 2.559 ipnn2 Linux 2.6.25- 14.8 7.9639 623.8 8.2042 927.0 0.773 2.21510 2.557 ipnn2 Linux 2.6.25- 14.4 7.5842 622.3 8.3272 920.0 0.745 2.22210 2.558 ipnn2 Linux 2.6.25- 14.2 7.6339 45.7 10.2 935.0 0.675 2.23860 2.554 ipnn2 Linux 2.6.25- 14.1 7.7175 263.7 10.1 929.0 0.762 2.22350 2.556 ipnn2 Linux 2.6.25- 13.9 8.1230 378.2 9.4343 975.0 0.752 2.25920 2.554 2.6.23: File & VM system latencies in microseconds - smaller is better ------------------------------------------------------------------------------- Host OS 0K File 10K File Mmap Prot Page 100fd Create Delete Create Delete Latency Fault Fault selct --------- ------------- ------ ------ ------ ------ ------- ----- ------- ----- ipnn2 Linux 2.6.23- 218.0 0.912 1.94010 2.626 ipnn2 Linux 2.6.23- 219.0 1.095 1.96400 2.597 ipnn2 Linux 2.6.23- 219.0 0.774 1.96640 2.603 ipnn2 Linux 2.6.23- 221.0 0.946 1.99950 2.601 ipnn2 Linux 2.6.23- 219.0 0.902 1.99160 2.733 ipnn2 Linux 2.6.23- 217.0 0.904 2.04790 2.601 ipnn2 Linux 2.6.23- 225.0 0.893 1.99620 2.600