From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 379CDD75BBA for ; Thu, 21 Nov 2024 04:57:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=PVTU19XXSVY7UlVaLaj149eRwdVFbApD/P8A55SEq2U=; b=FAV3KERfe0/yBQ+7CC0iHtpkdR Zz9w5HaMP64P3tKqmlCdT3I8pS+FGWG5kmy3Y6LLY5OGQXfPo/SG2AgiVhE8IOPpDgL3F5HwuqWQP gtM3d/EFEuWci8i8O11HHQglJphlLYJcT5gXV9JgqWSK7ck+dlhkwC5P6eK94RFLXUzq+3q7Z6M5R nyV3im6Vr+fuQkQY7VH00yTirYbFJaSRDHdVPv9XWeA1M11kPkWSPYAnpU1CJ7abaezYzXSD93l+l mM/DCpo0hTL3NNG+Ivlyzn6UWqftqfGVSKA2WPjamR4YchGjEQoNkRcmhwuVmE+gEZ0L8B0jDrYOJ U90SHxRw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tDzFp-0000000Gpd5-0hBo; Thu, 21 Nov 2024 04:57:21 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tDzFm-0000000Gpcg-3wz2 for linux-nvme@lists.infradead.org; Thu, 21 Nov 2024 04:57:20 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id CC6E968BEB; Thu, 21 Nov 2024 05:57:14 +0100 (CET) Date: Thu, 21 Nov 2024 05:57:14 +0100 From: Christoph Hellwig To: Jens Axboe Cc: Chaitanya Kulkarni , Saeed Mirzamohammadi , "linux-kernel@vger.kernel.org" , "linux-nvme@lists.infradead.org" , Ramanan Govindarajan , Sagi Grimberg , Paul Webb , Christoph Hellwig , Keith Busch Subject: Re: [bug-report] 5-9% FIO randomwrite ext4 perf regression on 6.12.y kernel Message-ID: <20241121045714.GA20680@lst.de> References: <392209D9-5AC6-4FDE-8D84-FB8A82AD9AEF@oracle.com> <0cfbfcf6-08f5-4d1b-82c4-729db9198896@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241120_205719_123512_F59815C8 X-CRM114-Status: GOOD ( 13.57 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Nov 20, 2024 at 06:20:12PM -0700, Jens Axboe wrote: > There's no way that commit is involved, the test as quoted doesn't even > touch write zeroes. Hence if there really is a regression here, then > it's either not easily bisectable, some error was injected while > bisecting, or the test itself is bimodal. ext4 actually has some weird lazy init code using write zeroes. So if the test actually wasn't a steady state one but only run for a short time after init, and the mentioned commit dropped the intel hack for deallocate as write zeroes it might actually make a difference. To check for that do a : /sys/block/nvmeXn1/queue/write_zeroes_max_bytes with and without that commit.