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From: Tejun Heo <tj@kernel.org>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Hannes Reinecke <hare@suse.de>, Hannes Reinecke <hare@kernel.org>,
	Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>,
	linux-nvme@lists.infradead.org
Subject: Re: [PATCH 1/4] nvme-tcp: per-controller I/O workqueues
Date: Wed, 3 Jul 2024 09:17:26 -1000	[thread overview]
Message-ID: <ZoWjxtyjHTC2r285@slm.duckdns.org> (raw)
In-Reply-To: <aaa404b1-72ac-4b15-8c30-a62ef2216004@grimberg.me>

Hello,

On Wed, Jul 03, 2024 at 10:14:14PM +0300, Sagi Grimberg wrote:
...
> None of these reasons are the claimed reason to use separate workqueues in
> this patch. The claim is that it is more efficient, i.e. has less overhead.
> 
> The commit msg is the following:
> "Implement per-controller I/O workqueues to reduce workqueue contention
> during I/O."

Hmm... it's not impossible for the concurrency accounting in pool_workqueues
to show up if the issue rate is *really* high but I'd be surprised if that
actually matters given that the backend pool is shared. Maybe I'm missing
something but I don't see a reason why multiple workqueues would be more
efficient than a shared one.

Thanks.

-- 
tejun


  reply	other threads:[~2024-07-03 19:17 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-03 13:50 [PATCH 0/4] nvme-tcp: improve scalability Hannes Reinecke
2024-07-03 13:50 ` [PATCH 1/4] nvme-tcp: per-controller I/O workqueues Hannes Reinecke
2024-07-03 14:11   ` Sagi Grimberg
2024-07-03 14:46     ` Hannes Reinecke
2024-07-03 15:16       ` Sagi Grimberg
2024-07-03 17:07         ` Tejun Heo
2024-07-03 19:14           ` Sagi Grimberg
2024-07-03 19:17             ` Tejun Heo [this message]
2024-07-03 19:41               ` Sagi Grimberg
2024-07-04  7:36               ` Hannes Reinecke
2024-07-05  7:10                 ` Christoph Hellwig
2024-07-05  8:11                   ` Hannes Reinecke
2024-07-05  8:16                     ` Jens Axboe
2024-07-04  5:36   ` Christoph Hellwig
2024-07-03 13:50 ` [PATCH 2/4] nvme-tcp: align I/O cpu with blk-mq mapping Hannes Reinecke
2024-07-03 14:19   ` Sagi Grimberg
2024-07-03 14:53     ` Hannes Reinecke
2024-07-03 15:03       ` Sagi Grimberg
2024-07-03 15:40         ` Hannes Reinecke
2024-07-03 19:38           ` Sagi Grimberg
2024-07-03 19:47             ` Sagi Grimberg
2024-07-04  6:43             ` Hannes Reinecke
2024-07-04  9:07               ` Sagi Grimberg
2024-07-04 14:03                 ` Hannes Reinecke
2024-07-04  5:37     ` Christoph Hellwig
2024-07-04  9:13       ` Sagi Grimberg
2024-07-03 13:50 ` [PATCH 3/4] workqueue: introduce helper workqueue_unbound_affinity_scope() Hannes Reinecke
2024-07-03 17:31   ` Tejun Heo
2024-07-04  6:04     ` Hannes Reinecke
2024-07-03 13:50 ` [PATCH 4/4] nvme-tcp: switch to 'cpu' affinity scope for unbound workqueues Hannes Reinecke
2024-07-03 14:22   ` Sagi Grimberg
2024-07-03 15:01     ` Hannes Reinecke
2024-07-03 15:09       ` Sagi Grimberg
2024-07-03 15:50         ` Hannes Reinecke
2024-07-04  9:11           ` Sagi Grimberg
2024-07-04 15:54             ` Hannes Reinecke
2024-07-05 11:48               ` Sagi Grimberg

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