From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93D64824B1; Mon, 1 Jul 2024 08:43:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719823398; cv=none; b=hGSSRiH7bim/Q9UzDs6X15uwD1aOmqJ+nBTUQaZTjiWgyANi67wgJk7tnIaQu7BXzoHNvGs1o9LkNDqCap4S8f6cbirnR9VeHrIt98sZdg08wrshn/SJVCvrZOFxBHA8ZdYVw/Sh65nsPlHXRiBHf4ZvZYDY0rOPs48dCZlTqlc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719823398; c=relaxed/simple; bh=iKKJnz8DOvSs+0IlwtcTPhx8Kpj5HEFRMbgY9GRZsiE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=kmtUdQZPvI7Uj3mDnhr9xnJBRqIgi1p64XOahqUIFRkfcvuI41EEZTIiFhQxYHvjvaJwY8IUFW8WNB1cDXL918If+yqi6/JFar+5H191ZIDlUFIkgGhZoIVCEjpYJvUqYpmdrCBsZ4kcQTDJ6xcRb/96cvAfTbkPacgJInNehU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de; spf=pass smtp.mailfrom=suse.de; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=cKUI307r; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=tEKfHShe; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b=cKUI307r; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b=tEKfHShe; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=suse.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="cKUI307r"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="tEKfHShe"; dkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de header.b="cKUI307r"; dkim=permerror (0-bit key) header.d=suse.de header.i=@suse.de header.b="tEKfHShe" Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (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 B10D221AB2; Mon, 1 Jul 2024 08:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1719823394; 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=dIGflQywJ8dMNdlKWrZr5XV9go3j7auton/EPKSlbOY=; b=cKUI307rRb/HXjE2LY3/FdpZ+60oCL5DdFYtsOSUJh3imAPs1DMSM8hlrwlKI9rBeZff47 UOHTlB1YkZBO7cJsBCBrNpzXTtwMXRkkSTjHTY+1bYh4c9BScxhovb9lB1iI6l8O+xXbht xRBF0Afm3Djlz6qZy7LXL2wXcjl+OhA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1719823394; 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=dIGflQywJ8dMNdlKWrZr5XV9go3j7auton/EPKSlbOY=; b=tEKfHSheR0o5BNtMV3BsolCPze4YAKmPupn+SeMGYwRh0MhJFP5hH5Qp6WUHoUrsBGZby7 wQccriqBj0pX/iDQ== Authentication-Results: smtp-out1.suse.de; dkim=pass header.d=suse.de header.s=susede2_rsa header.b=cKUI307r; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=tEKfHShe DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1719823394; 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=dIGflQywJ8dMNdlKWrZr5XV9go3j7auton/EPKSlbOY=; b=cKUI307rRb/HXjE2LY3/FdpZ+60oCL5DdFYtsOSUJh3imAPs1DMSM8hlrwlKI9rBeZff47 UOHTlB1YkZBO7cJsBCBrNpzXTtwMXRkkSTjHTY+1bYh4c9BScxhovb9lB1iI6l8O+xXbht xRBF0Afm3Djlz6qZy7LXL2wXcjl+OhA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1719823394; 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=dIGflQywJ8dMNdlKWrZr5XV9go3j7auton/EPKSlbOY=; b=tEKfHSheR0o5BNtMV3BsolCPze4YAKmPupn+SeMGYwRh0MhJFP5hH5Qp6WUHoUrsBGZby7 wQccriqBj0pX/iDQ== Received: from imap1.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 imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 7A3C313800; Mon, 1 Jul 2024 08:43:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id FdU9HSJsgmZnBwAAD6G6ig (envelope-from ); Mon, 01 Jul 2024 08:43:14 +0000 Message-ID: <0d8a5256-9719-45c5-b098-237b5a82fd36@suse.de> Date: Mon, 1 Jul 2024 10:43:14 +0200 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/3] lib/group_cpus.c: honor housekeeping config when grouping CPUs To: Ming Lei , Daniel Wagner Cc: Jens Axboe , Keith Busch , Sagi Grimberg , Thomas Gleixner , Christoph Hellwig , Frederic Weisbecker , Mel Gorman , Sridhar Balaraman , "brookxu.cn" , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org References: <20240627-isolcpus-io-queues-v2-0-26a32e3c4f75@suse.de> <20240627-isolcpus-io-queues-v2-3-26a32e3c4f75@suse.de> Content-Language: en-US From: Hannes Reinecke In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-3.00 / 50.00]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; XM_UA_NO_VERSION(0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; ARC_NA(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; RCPT_COUNT_TWELVE(0.00)[14]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; FREEMAIL_CC(0.00)[kernel.dk,kernel.org,grimberg.me,linutronix.de,lst.de,suse.com,suse.de,parallelwireless.com,gmail.com,vger.kernel.org,lists.infradead.org]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[]; DKIM_TRACE(0.00)[suse.de:+]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.de:email,suse.de:dkim] X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Queue-Id: B10D221AB2 X-Spam-Flag: NO X-Spam-Score: -3.00 X-Spam-Level: On 7/1/24 09:21, Ming Lei wrote: > On Mon, Jul 01, 2024 at 09:08:32AM +0200, Daniel Wagner wrote: >> On Sun, Jun 30, 2024 at 09:39:59PM GMT, Ming Lei wrote: >>>> Make group_cpus_evenly aware of isolcpus configuration and use the >>>> housekeeping CPU mask as base for distributing the available CPUs into >>>> groups. >>>> >>>> Fixes: 11ea68f553e2 ("genirq, sched/isolation: Isolate from handling managed interrupts") >>> >>> isolated CPUs are actually handled when figuring out irq effective mask, >>> so not sure how commit 11ea68f553e2 is wrong, and what is fixed in this >>> patch from user viewpoint? >> >> IO queues are allocated/spread on the isolated CPUs and if there is an >> thread submitting IOs from an isolated CPU it will cause noise on the >> isolated CPUs. The question is this a use case you need/want to support? > > I have talked RH Openshift team weeks ago and they have such usage. > > userspace is free to run any application from isolated CPUs via 'taskset > -c' even though 'isolcpus=' is passed from command line. > > Kernel can not add such new constraint on userspace. > >> We have customers who are complaining that even with isolcpus provided >> they still see IO noise on the isolated CPUs. > > That is another issue, which has been fixed by the following patch: > > a46c27026da1 blk-mq: don't schedule block kworker on isolated CPUs > Hmm. Just when I thought I understood the issue ... How is this supposed to work, then, given that I/O can be initiated from the isolated CPUs? I would have accepted that we have two scheduling domains, blk-mq is spread across all cpus, and the blk-mq cpusets are arranged according to the isolcpu settings. Then we can initiate I/O from the isolated cpus, and the scheduler would 'magically' ensure that everything is only run on isolated cpus. But that patch would completely counteract such a setup, as during I/O we more often than not will invoke kblockd, which then would cause cross-talk on non-isolated cpus. What is the idea here? Confused, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich