From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matus Kocka Subject: Regression ~7% write, 3.17.1 vs 3.18.0rc5 Date: Fri, 28 Nov 2014 18:45:37 +0100 Message-ID: <5478B4C1.5060203@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE To: linux-fsdevel@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54970 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750901AbaK1Rpl (ORCPT ); Fri, 28 Nov 2014 12:45:41 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sASHjegQ001280 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 28 Nov 2014 12:45:41 -0500 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hello, we see the ~7% regression in the initial WRITE on xfs in in-cache mode=20 by IOZONE test between 3.17.1-306.el7 and 3.18.0-0.rc5.git0.1.el7 (respectively=20 3.18.0-0.rc3.git0.2.el7) By in-cache mode we mean that file fits into the OS cache. =46or big file-sizes >4GiB (out of cache mode) there is no performance = drop. [Files:=20 https://www.dropbox.com/sh/2sx0ejt73n4idcp/AAA0nYhZTDAMGigJ-B5yqTwga?dl= =3D0] 1, Firstly, (xfs_SATA.pdf) we see the ~7% regression in the in-cache IOZONE test on 1 TB SATA disk with cfq io-elevator, 2, We also see it (xfs_write.pdf) using same in-cache test on the fast pci SSD disk (RealSSD P320h 350GB) 3, We have tried direct-io tests on the same pci SSD with no regression= =20 (directio.pdf) It seems that this regression is related to cache since DIRECT IO and=20 out-of-cache tests do not have the regression. Also, rewrite test does not show any=20 regression. Would somebody from the developers be interested to look into it and tr= y=20 to hunt down this bug? We can provide more details regarding our testing methodology but we=20 have neither capacity nor expertise to debug it ourselves. --=20 Matus Kocka Quality Assurance Associate Red Hat Czech s.r.o. Purky=C5=88ova 99/71, 612 45, Brno, Czech Republic tel.: +420 532 294 793 direct: 8262793 email: mkocka [at] redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html