From: Andrej Gelenberg <andrej.gelenberg@udo.edu>
To: Douglas Gilbert <dgilbert@interlog.com>
Cc: JBottomley@parallels.com, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org, hch@lst.de,
martin.petersen@oracle.com, elliott@hp.com
Subject: Re: CONFIG_SCSI_MQ_DEFAULT cause slow direct write speed to usb stick
Date: Wed, 11 Feb 2015 14:02:37 +0100 [thread overview]
Message-ID: <20150211140237.29101167@bigpc> (raw)
In-Reply-To: <54DA81CA.2030303@interlog.com>
Hi,
my problem was, that write speed to the device is got really slow from
7 Mb/s to 250 Kb/s, so 16.76 Mb/sec is probably the speed limitation of
the uSD Card or is close to that. Do you activated blk-mq for scsi in
kernel config or in boot parameters?
Regards,
Andrej
On Tue, 10 Feb 2015 17:10:18 -0500
Douglas Gilbert <dgilbert@interlog.com> wrote:
> Here is an example:
>
> # ddpt if=/dev/sg1 bs=512 of=x.bin
> 1953792+0 records in
> 1953792+0 records out
> 1281 retries after EAGAIN error(s) during IO
> time to transfer data: 59.678788 secs at 16.76 MB/sec
>
> That is not a bad transfer time but other utilities
> or drivers might dwell longer on those (nuisance) EAGAINs.
prev parent reply other threads:[~2015-02-11 13:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-10 18:50 CONFIG_SCSI_MQ_DEFAULT cause slow direct write speed to usb stick Andrej Gelenberg
2015-02-10 22:10 ` Douglas Gilbert
2015-02-11 13:02 ` Andrej Gelenberg [this message]
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