From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
Keith Busch <kbusch@kernel.org>,
linux-nvme@lists.infradead.org
Subject: Re: [PATCH] nvme-tcp: align I/O cpu with blk-mq mapping
Date: Wed, 19 Jun 2024 07:30:15 +0200 [thread overview]
Message-ID: <20240619053015.GB29159@lst.de> (raw)
In-Reply-To: <20240618120345.64761-1-hare@kernel.org>
On Tue, Jun 18, 2024 at 02:03:45PM +0200, Hannes Reinecke wrote:
> Add a new module parameter 'wq_affinity' to spread the I/O
> over all cpus within the blk-mq hctx mapping for the queue.
> This avoids bouncing I/O between cpus when we have less
> hardware queues than cpus.
What is the benefit when setting it? What is the downside? Why do you
think it needs to be conditional?
> + }
> if (wq_unbound)
> queue->io_cpu = WORK_CPU_UNBOUND;
> + else if (wq_affinity) {
Missing curly braces. But this also means the wq_unbound options
is incompatible with your new one.
> + } else
> queue->io_cpu = cpumask_next_wrap(n - 1, cpu_online_mask, -1, false);
Overly long line here.
next prev parent reply other threads:[~2024-06-19 5:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-18 12:03 [PATCH] nvme-tcp: align I/O cpu with blk-mq mapping Hannes Reinecke
2024-06-19 5:30 ` Christoph Hellwig [this message]
2024-06-19 8:57 ` Sagi Grimberg
2024-06-19 10:01 ` Hannes Reinecke
2024-06-19 10:14 ` Sagi Grimberg
2024-06-19 10:09 ` Hannes Reinecke
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