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From: Keith Busch <kbusch@kernel.org>
To: Nikhil Sambhus <nikhilsambhus@gmail.com>
Cc: linux-block@vger.kernel.org
Subject: Re: Error while enabling io_poll for NVMe SSD
Date: Mon, 18 Mar 2019 16:21:34 -0600	[thread overview]
Message-ID: <20190318222133.GA24176@localhost.localdomain> (raw)
In-Reply-To: <CAFQ9A4Zc8Fc4bDyAsiduTw4kTpxR=dVZr7LUdqUkvQSu1CaGpg@mail.gmail.com>

On Mon, Mar 18, 2019 at 06:14:01PM -0400, Nikhil Sambhus wrote:
> Hi,
> 
> On a Linux Kernel 5.0.0+ machine (Ubuntu 16.04)  I am using the
> following command as a root user to enable polling for a NVMe SSD
> device.
> 
> # echo 1 > /sys/block/nvme2n1/queue/io_poll
> 
> I get the following error:
> 
> bash: echo: write error: Invalid argument
> 
> The current value of io_poll is 0.

Be sure to turn on the polling queues in the nvme driver. There are none
by default. The kernel parameter to that enable them is:

  nvme.poll_queues=X

Where 'X' is the number of polling queues. I'd recommend at least 1 per
CPU socket, but more is better.

  reply	other threads:[~2019-03-18 22:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-18 22:14 Error while enabling io_poll for NVMe SSD Nikhil Sambhus
2019-03-18 22:21 ` Keith Busch [this message]
2019-03-19 14:36   ` Nikhil Sambhus

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