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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10E6AEB64DD for ; Tue, 11 Jul 2023 05:42:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229449AbjGKFmW (ORCPT ); Tue, 11 Jul 2023 01:42:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230417AbjGKFmT (ORCPT ); Tue, 11 Jul 2023 01:42:19 -0400 Received: from mail.lichtvoll.de (luna.lichtvoll.de [194.150.191.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EAD8E57 for ; Mon, 10 Jul 2023 22:42:18 -0700 (PDT) Received: from 127.0.0.1 (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by mail.lichtvoll.de (Postfix) with ESMTPSA id 5DB4173AFC5; Tue, 11 Jul 2023 07:33:37 +0200 (CEST) Authentication-Results: mail.lichtvoll.de; auth=pass smtp.auth=martin smtp.mailfrom=martin@lichtvoll.de From: Martin Steigerwald To: linux-btrfs@vger.kernel.org, Tim Cuthbertson Subject: Re: Scrub of my nvme SSD has slowed by about 2/3 Date: Tue, 11 Jul 2023 07:33:36 +0200 Message-ID: <5690570.DvuYhMxLoT@lichtvoll.de> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Tim Cuthbertson - 03.07.23, 22:19:50 CEST: > Yesterday, I noticed that a scrub of my main system filesystem has > slowed from about 2.9 gb/sec to about 949 mb/sec. My scrub used to run > in about 12 seconds, now it is taking 51 seconds. I had just > installed Linux kernel 6.4.1 on Arch Linux, upgrading from 6.3.9. At > first I suspected the new kernel, but now I am not so sure. > > I have btrfs-progs v 6.3.2-1. It was last upgraded on June 23. I can confirm this with similar values. v6.3 was fine, with scrub speeds from 1.8 to 2.6 GiB/s, v6.4 only has a bit less 1 GiB/s. atop shows 100% utilization of NVME SSD which is odd at less than 1 GiB/ s sequential I/O and a lot of kworker threads doing about 200-300% of system time CPU utilization. This is with ThinkPad T14 AMD Gen 1 with AMD Ryzen 7 PRO 4750U and 32 GiB RAM on Samsung 980 Pro 2TB NVME SSD connected via PCIe 3. The hardware can definitely do more throughput even with "just" PCIe 3. -- Martin