From: Richard Miller <9fans@hamnavoe.com>
To: 9fans@9fans.net
Subject: Re: [9fans] usb slowness
Date: Wed, 7 Mar 2012 15:27:31 +0000 [thread overview]
Message-ID: <31d2b19469a4d6da457fe426ec14417c@hamnavoe.com> (raw)
In-Reply-To: <2579b9.4d6b93e5.B75p.mx@tumtum.plumbweb.net>
> does anybody get less than 10 sec for
>
> dd -if /dev/sdU0.0/data -of /dev/null -count 1024 -bs 65536 ?
>
> or even less than 20 sec?
10.4 sec on a sheevaplug (with 1 microframe interrupt threshold).
By the way, everyone has been very tactful not to point out my
silly mistake in saying:
> ... You can use time(1) while
> reading usb disk to see if cpu is really the bottleneck, or if
> in fact your machine is spending most of its time waiting for
> a usb interrupt.
Of course most of the user+sys cpu time involved in reading from usb
disk will be charged to the usb/disk process (normally a subprocess of
usbd), not to user command doing the reading.
next prev parent reply other threads:[~2012-03-07 15:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-04 1:56 Tristan
2012-03-05 15:46 ` erik quanstrom
2012-03-05 16:05 ` Richard Miller
2012-03-05 16:14 ` erik quanstrom
2012-03-05 16:20 ` Richard Miller
2012-03-06 13:19 ` Tristan
2012-03-06 15:36 ` Tristan
2012-03-06 16:10 ` Richard Miller
2012-03-06 18:55 ` erik quanstrom
2012-03-06 22:22 ` Tristan
2012-03-07 5:50 ` Tristan
2012-03-07 5:53 ` Tristan
2012-03-07 9:31 ` Charles Forsyth
2012-03-10 3:13 ` [9fans] donehead changed before ack Tristan
2012-03-10 12:33 ` erik quanstrom
2012-03-10 15:14 ` Tristan
2012-03-07 15:27 ` Richard Miller [this message]
2012-03-05 15:56 ` [9fans] usb slowness Richard Miller
2012-03-06 0:01 ` Tristan
2012-03-06 10:39 ` Richard Miller
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