From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="EKlH9VGo"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="PDvSxD86" Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2a07:de40:b251:101:10:150:64:1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DF9810C2 for ; Thu, 7 Dec 2023 05:49:15 -0800 (PST) Received: from imap2.dmz-prg2.suse.org (imap2.dmz-prg2.suse.org [10.150.64.98]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 0ADEC21B3D; Thu, 7 Dec 2023 13:49:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1701956954; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=K3yqzIpfk4tW7oRiQjz5OLluc6v3BUjDnldmkuuvyXM=; b=EKlH9VGo1SXji9Z4B56+azdYWitfOL2odqv87xp9zTXtJdFwGQb1lGlqMJCizGbxWOgE9t 1bGVlU6mKV7qTLxsnmPnu/K10RrcEpkzi/XczM2ElPHwZ/djLvZtOXB4mVmZMjoTqboR++ C7k58+xaI8EYefnMI6XC7jx1lGhrU/c= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1701956954; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=K3yqzIpfk4tW7oRiQjz5OLluc6v3BUjDnldmkuuvyXM=; b=PDvSxD86Jw8k+2J5SNbTodmGf1xfipS7eRxrQwF+b+zmZfQf2L+BYRfr+RSG1QGfOxZG27 nmm1cqsoyS9re4Bw== Received: from imap2.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap2.dmz-prg2.suse.org (Postfix) with ESMTPS id EE39B13907; Thu, 7 Dec 2023 13:49:11 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap2.dmz-prg2.suse.org with ESMTPSA id wEyaIlfNcWU3GgAAn2gu4w (envelope-from ); Thu, 07 Dec 2023 13:49:11 +0000 Date: Fri, 8 Dec 2023 00:49:02 +1100 From: David Disseldorp To: Qu Wenruo Cc: fstests@vger.kernel.org, Qu Wenruo Subject: Re: [PATCH 0/5] btrfs/282: resolve intermittent failures Message-ID: <20231208004902.3df2bed2@echidna> In-Reply-To: <949dd5fe-560f-4986-b653-c84aa9afd778@gmx.com> References: <20231207072056.14588-1-ddiss@suse.de> <949dd5fe-560f-4986-b653-c84aa9afd778@gmx.com> Precedence: bulk X-Mailing-List: fstests@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [0.40 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; FREEMAIL_ENVRCPT(0.00)[gmx.com]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_SOME(0.00)[]; RCVD_COUNT_THREE(0.00)[3]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FREEMAIL_TO(0.00)[gmx.com]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-0.00)[24.23%] Authentication-Results: smtp-out1.suse.de; none X-Spam-Level: X-Spam-Score: 0.40 On Thu, 7 Dec 2023 20:19:00 +1030, Qu Wenruo wrote: > On 2023/12/7 17:50, David Disseldorp wrote: > > btrfs/282 fails intermittently under some circumstances. This patchset > > adds dmdelay to make storage latencies more uniform and slightly > > increases throttled rate tolerances. > > My concern using dm_delay is, is the delay per-merged-bio or something else? > > If the delay is only per-bio (after merge), then I'm afraid it would not > be good enough. The dmdelay device presents itself as a regular block device, so I think delay_map()->delay_bio() handling comes after any merges. > The bio plug we use in scrub can have much higher chance to result a > difference in the scrub speed. > > We may want a delay behavior which can take bio size into consideration > at least. Should we manipulate it a bit by fiddling with queue/max_sectors_kb and queue/nomerges? Thanks, David