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 66BABEB64DD for ; Fri, 28 Jul 2023 21:14:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231494AbjG1VO6 (ORCPT ); Fri, 28 Jul 2023 17:14:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233578AbjG1VO5 (ORCPT ); Fri, 28 Jul 2023 17:14:57 -0400 Received: from mail.lichtvoll.de (lichtvoll.de [IPv6:2001:67c:14c:12f::11:100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9056B44AB for ; Fri, 28 Jul 2023 14:14:54 -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 D182E75BC86; Fri, 28 Jul 2023 23:14:50 +0200 (CEST) Authentication-Results: mail.lichtvoll.de; auth=pass smtp.auth=martin smtp.mailfrom=martin@lichtvoll.de From: Martin Steigerwald To: dsterba@suse.cz Cc: linux-btrfs@vger.kernel.org, Qu Wenruo Subject: Re: [PATCH 0/5] btrfs: scrub: improve the scrub performance Date: Fri, 28 Jul 2023 23:14:50 +0200 Message-ID: <1738327.QkHrqEjB74@lichtvoll.de> In-Reply-To: <20230728165037.GJ17922@twin.jikos.cz> References: <6543972.G0QQBjFxQf@lichtvoll.de> <20230728165037.GJ17922@twin.jikos.cz> 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 David Sterba - 28.07.23, 18:50:37 CEST: > On Fri, Jul 28, 2023 at 02:38:35PM +0200, Martin Steigerwald wrote: > > Qu Wenruo - 28.07.23, 13:14:03 CEST: > > > The first 3 patches would greately improve the scrub read > > > performance, but unfortunately it's still not as fast as the > > > pre-6.4 kernels. (2.2GiB/s vs 3.0GiB/s), but still much better > > > than 6.4 kernels (2.2GiB vs 1.0GiB/s). > > > > Thanks for the patch set. > > > > What is the reason for not going back to the performance of the > > pre-6.4 kernel? Isn't it possible with the new scrubbing method? In > > that case what improvements does the new scrubbing code have that > > warrant to have a lower performance? > > Lower performance was not expected and needs to be brought back. A > minor decrease would be tolerable but that's something around 5%, not > 60%. Okay. Best of success with improving performance again. > > Just like to understand the background of this a bit more. I do not > > mind a bit lower performance too much, especially in case it is > > outweighed by other benefits. > > The code in scrub was from 3.0 times and since then new features have > been implemented, extending the code became hard over time so a bigger > update was done restructuring how the IO is done. Okay, thanks for explaining. -- Martin