From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: Hannes Reinecke <hare@kernel.org>, Christoph Hellwig <hch@lst.de>,
Keith Busch <kbusch@kernel.org>,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH 2/4] nvme-tcp: align I/O cpu with blk-mq mapping
Date: Thu, 4 Jul 2024 07:37:25 +0200 [thread overview]
Message-ID: <20240704053725.GB19735@lst.de> (raw)
In-Reply-To: <b6702586-12c4-4390-9085-2cc6d9fbb462@grimberg.me>
On Wed, Jul 03, 2024 at 05:19:39PM +0300, Sagi Grimberg wrote:
>
>
> On 03/07/2024 16:50, Hannes Reinecke wrote:
>> When 'wq_unbound' is selected we should select the
>> the first CPU from a given blk-mq hctx mapping to queue
>> the tcp workqueue item. With this we can instruct the
>> workqueue code to keep the I/O affinity and avoid
>> a performance penalty.
>
> wq_unbound is designed to keep io_cpu to be UNBOUND, my recollection
> was the the person introducing it was trying to make the io_cpu always be
> on a specific NUMA node, or a subset of cpus within a numa node. So he uses
> that and tinkers with wq cpumask via sysfs.
Honestly, I think we really should kill this unbound module paramter
before it causes more harm.
next prev parent reply other threads:[~2024-07-04 5:37 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
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 [this message]
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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