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Fri, 05 Jul 2024 08:11:22 +0000 Message-ID: <8beb0e36-af31-4633-ae2a-afa6bcec5a14@suse.de> Date: Fri, 5 Jul 2024 10:11:21 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] nvme-tcp: per-controller I/O workqueues To: Christoph Hellwig Cc: Tejun Heo , Sagi Grimberg , Hannes Reinecke , Keith Busch , linux-nvme@lists.infradead.org References: <20240703135021.34143-1-hare@kernel.org> <20240703135021.34143-2-hare@kernel.org> <7e4444d0-f156-439e-9363-4beb86bb6248@grimberg.me> <9de5d83c-4b05-4f69-8ab4-b4aa65e5ec62@suse.de> <20240705071022.GA13302@lst.de> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20240705071022.GA13302@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-5.50 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; DWL_DNSWL_LOW(-1.00)[suse.de:dkim]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-0.997]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; XM_UA_NO_VERSION(0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_TLS_ALL(0.00)[]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; RCPT_COUNT_FIVE(0.00)[6]; FROM_HAS_DN(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DKIM_TRACE(0.00)[suse.de:+] X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Queue-Id: 9F60221B46 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240705_011124_945113_9371842B X-CRM114-Status: GOOD ( 10.31 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 7/5/24 09:10, Christoph Hellwig wrote: > Btw, I don't think brd is what we should optimize for. brd does > synchronous I/O from ->submit_bio which makes it very non-typical. > Trying to get this as good as possible for QD=1 might be fine, > but once we have deeper queue depth and/or bigger I/O size it will > use a lot more time in the submission context (aka the workqueues here) > than a real device. > Hmm. brd was the simplest choice to get a high-bandwidth target. I'll check if a get a similar performance with null-blk. Cheers, 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