From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=195.135.223.131 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792570780; b=U3ZWVj0GxWpun5wvxUAjhMGSJftlDz5hyzAHXML3SEAyccL8oBX9SoV11qQTfAxlxvDB y/RIdN1hp+xbkVfapOrG7tNNiuvSAaxgDQncklOeQLt0XXynUiSmQ8QS2O9dYZzX8dfYk 4QoQOfnVPyyEN4ZI25c2mFMGqAxCar4DRei7Khe/kir78w2toPYqv7bMzK7C862lnGQqm xv8NieVqoQC5UUq3PHRpXS2oNz1bRntWBRBM03mdcCOOoEBtLH82pE4ygE2sz9LlVDfXr HgQtjDPALbhbWR90s+HW4wIsUm/kwEcyVup6lu665w7ggqdfUy9r8L3eSkDu/+CzPRA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792570780; h=DMARC-Filter:Received:Received:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To:X-Rspamd-Pre-Result:X-Spam-Flag:X-Spam-Score: X-Spamd-Result:X-Rspamd-Server:X-Rspamd-Queue-Id:X-Spam-Level: X-Rspamd-Action:X-Rspamd-Pre-Result; bh=UXbOGUpZm15en8KHgC3tGiUJ4oIJt1ZsmGR453cgBIY=; b=PSPdsajKwNSXl3g2sg2nzyKDzKzYKxKuLggg9/YmXOBu/dlnDqjeU5G/pw/ggYh7EOCY 8f2ii7Rhb3VRsh6pULhs3ADTmusn/J8d83eyR7eq06z1FHeLm7d4ROqFQ7StPFjg//tyU Gqtux4liOOpjbkXXYkWeXcEz/6ItgXcoMQPKMCcaRAF6n23tpXVDyz1t3TAdTsQNhrwq/ tKcjbL6aS9W57vt6TO4AONmjooHf0NwPZJ0OjnJHghtDtVvIe7ixjFs97f6F4tNieW3nG Cznzeskdi0luUfKFjWpoZTORXM1YiTJW5ggGshk8TgmTtKcmHZj58k+WoCZJQIcjbmw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=suse.de; spf=pass smtp.mailfrom=suse.de; arc=none smtp.remote-ip=195.135.223.131 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.223.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59A96606A31B for ; Wed, 21 Oct 2026 08:19:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 59A96606A31B 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 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-out2.suse.de (Postfix) with ESMTPS id 9F14F1F457; Wed, 21 Oct 2026 08:19:38 +0000 (UTC) Authentication-Results: smtp-out2.suse.de; none 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 67C73134FD; Wed, 21 Oct 2026 08:19:38 +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 BnZkEZp12GovSgAAD6G6ig (envelope-from ); Wed, 21 Oct 2026 08:19:38 +0000 Date: Wed, 21 Oct 2026 10:19:37 +0200 From: Daniel Wagner To: Hannes Reinecke Cc: Saravanan D , linux-nvme@lists.infradead.org, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, axboe@kernel.dk, nilay@linux.ibm.com, sgogte@purestorage.com, hare@kernel.org, linux-kernel@vger.kernel.org, iyamahata@crusoe.ai, kiyer@crusoe.ai, ganbalagane@crusoe.ai, sjpark@crusoe.ai Subject: Re: [PATCH v5 2/2] nvme-tcp: allow setting per-queue io_cpu through sysfs Message-ID: <79b5a23a-5ecf-4e96-85c8-031b5eca2867@flourine.local> References: <20261018010059.83120-1-saravanand@crusoe.ai> <20261018010059.83120-3-saravanand@crusoe.ai> <0ee4d281-61b4-458e-92c6-7fff3e50c0ec@flourine.local> <72fce5bb-b256-42aa-8844-f970c4480ad3@suse.de> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <72fce5bb-b256-42aa-8844-f970c4480ad3@suse.de> X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spam-Flag: NO X-Spam-Score: -4.00 X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[] X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Rspamd-Queue-Id: 9F14F1F457 X-Spam-Level: X-Rspamd-Action: no action X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated On Wed, Oct 21, 2026 at 09:21:09AM +0200, Hannes Reinecke wrote: > > I think it make sense to allow that the user can change queue CPU > > pinning during runtime even with isolcpu enabled. And then the question > > is should this be connected to cgroups? > > Not sure if cgroups is the right concept here; cgroups are user/ > application centric whereas nvme-tcp is pretty much queue/cpu centric. > IE after all the cgroup calculations are done. > Don't think cgroups are a good fit here. There was a lot of discussion during Linux Plumbers on how to configure a system for the isolcpus case at runtime. From what I understand, the preferred interface for this is cgroups. Hence, pinning the CPU for this work is likely a target for it, though I don't think there is a need to figure it out right now. I just wanted to highlight this point. However, to make this truly user-friendly, I think nvme-cli should be extended so it is aware of this and can configure it directly. I've merged Nilay's --nr-io-queues patches, so this is the natural next feature nvme-cli should support; see commit: e170d6985797 ("news: document the use of --nr-io-queues during nvme connect") I would also really like to have a blktest for this as well.