From: Keith Mannthey Subject: Ext4 performance regression: Post 2.6.30 Date: Sun, 28 Mar 2010 23:25:35 -0700 Message-ID: <1269843935.13369.52.camel@keith-laptop> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit To: linux-ext4 Return-path: Received: from e8.ny.us.ibm.com ([32.97.182.138]:49610 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752367Ab0C2GZY (ORCPT ); Mon, 29 Mar 2010 02:25:24 -0400 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by e8.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id o2T6Gdw5030946 for ; Mon, 29 Mar 2010 02:16:39 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o2T6PLxh094716 for ; Mon, 29 Mar 2010 02:25:23 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o2T6PLks032659 for ; Mon, 29 Mar 2010 02:25:21 -0400 Received: from [9.65.56.193] (sig-9-65-56-193.mts.ibm.com [9.65.56.193]) by d01av01.pok.ibm.com (8.14.3/8.13.1/NCO v10.0 AVin) with ESMTP id o2T6PKY1032649 for ; Mon, 29 Mar 2010 02:25:21 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: After 2.6.30 I am seeing large performance regressions on a raid setup. I am working to publish a larger amount of data but I wanted to get some quick data out about what I am seeing. The test (FFSB test suite) I am running is basically random direct io writes. The below data is from 128 threads all doing these random writes. 1 and 32 thread results are not as drastically bad but 2.6.30 has the strongest results. Under a mailserver workload I see similar performance impacts at this same kernel change point. I hope to publish better data soon. Several other workload types do not show this performance regression. 2.6.30: Total Results =============== Op Name Transactions Trans/sec % Trans % Op Weight Throughput ======= ============ ========= ======= =========== ========== write : 9015040 29561.46 100.000% 100.000% 115MB/sec - 29561.46 Transactions per Second Any kernel past 2.6.30. This is from 2.6.31-rc1: Total Results =============== Op Name Transactions Trans/sec % Trans % Op Weight Throughput ======= ============ ========= ======= =========== ========== write : 3185920 10120.50 100.000% 100.000% 39.5MB/sec