Flexible I/O Tester development
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From: Jens Axboe <axboe@kernel.dk>
To: Matthew Eaton <m.eaton82@gmail.com>, fio@vger.kernel.org
Subject: Re: Iosched_switch error
Date: Tue, 5 Jul 2016 14:17:57 -0600	[thread overview]
Message-ID: <577C15F5.2040005@kernel.dk> (raw)
In-Reply-To: <CAF+0mvny52U+Z9LWaHyuEVZjem8q8X11bF6fp-qepa4Y6W8pcQ@mail.gmail.com>

On 06/30/2016 06:05 PM, Matthew Eaton wrote:
> Hi Jens,
>
> I have run into this error when using ioscheduler=noop in my job
> files. I only run into the error when specifying unsupported devices
> such as nvme or md raid device. Should this be a fatal error? I ask
> because sometimes I want to run the same job on various devices.
>
> sudo fname=/dev/nvme0n1 ./fio seqread.ini
> seq-read: (g=0): rw=read, bs=128K-128K/128K-128K/128K-128K,
> ioengine=libaio, iodepth=32
> fio-2.12-3-g8a09
> Starting 1 process
> fio: io scheduler noop not found
> fio: pid=5541, err=22/file:backend.c:1306, func=iosched_switch,
> error=Invalid argument

IO scheduler switching can only work, if the device is using an IO 
scheduler. md/raid devices are not, and nvme is driven by blk-mq, which 
doesn't have an IO scheduler either. That's why these devices fail for you.

-- 
Jens Axboe



      reply	other threads:[~2016-07-05 20:17 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-01  0:05 Iosched_switch error Matthew Eaton
2016-07-05 20:17 ` Jens Axboe [this message]

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