From: Duncan Sands <duncan.sands@math.u-psud.fr>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: "René Rebe" <rene@exactcode.de>, linux-kernel@vger.kernel.org
Subject: Re: MAX_USBFS_BUFFER_SIZE
Date: Fri, 3 Mar 2006 09:12:11 +0100 [thread overview]
Message-ID: <200603030912.11622.duncan.sands@math.u-psud.fr> (raw)
In-Reply-To: <20060302130519.588b18a2.zaitcev@redhat.com>
> Have you ever considered how many TDs have to be allocated to transfer
> a data buffer this big? No, seriously. If your application cannot deliver
> the tranfer speeds with 16KB URBs, we ought to consider if the combination
> of our USB stack, usbfs, libusb and the application ought to get serious
> performance enhancing surgery. The problem is obviously in the software
> overhead.
If you queue a large number of 16KB urbs, rather than one jumbo urb,
does that make any difference to the number of TDs allocated? I thought
TDs were allocated for all queued urbs at the moment they are queued...
Ciao,
Duncan.
next prev parent reply other threads:[~2006-03-03 8:12 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-01 20:16 MAX_USBFS_BUFFER_SIZE René Rebe
2006-03-01 20:53 ` MAX_USBFS_BUFFER_SIZE Oliver Neukum
2006-03-01 21:32 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-01 21:42 ` MAX_USBFS_BUFFER_SIZE René Rebe
2006-03-01 21:54 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-01 22:34 ` MAX_USBFS_BUFFER_SIZE Olivier Galibert
2006-03-01 22:41 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-01 23:25 ` MAX_USBFS_BUFFER_SIZE Olivier Galibert
2006-03-01 23:37 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-02 9:04 ` MAX_USBFS_BUFFER_SIZE René Rebe
2006-03-02 16:47 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-02 16:03 ` MAX_USBFS_BUFFER_SIZE René Rebe
2006-03-02 16:47 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-01 21:59 ` MAX_USBFS_BUFFER_SIZE Duncan Sands
2006-03-03 10:34 ` MAX_USBFS_BUFFER_SIZE Oliver Neukum
[not found] ` <mailman.1141249502.22706.linux-kernel2news@redhat.com>
2006-03-02 21:05 ` MAX_USBFS_BUFFER_SIZE Pete Zaitcev
2006-03-03 7:27 ` MAX_USBFS_BUFFER_SIZE René Rebe
2006-03-03 20:32 ` MAX_USBFS_BUFFER_SIZE Greg KH
2006-03-03 8:12 ` Duncan Sands [this message]
2006-03-03 10:29 ` MAX_USBFS_BUFFER_SIZE Oliver Neukum
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