xqcam speed figures

To: linux-connectix@crynwr.com
Subject: xqcam speed figures
From: nelson@crynwr.com (Russell Nelson)
Date: Fri, 12 Jan 96 23:36 EST
From crynwr.com!nelson Fri Jan 12 23: 42:08 1996
In-Reply-To: <199601130007.QAA15585@inle.hhhh.org>
References: <199601130007.QAA15585@inle.hhhh.org>

Wim Lewis writes:

 > A quick calculation shows that it takes a minimum of 320x240x(3/2)x6 
 > or 691200 I/O operations to fetch a 320x240x6 frame, which means
 > my fastest numbers are doing about 1 million I/O ops per second. 
 > My (unsupported) hunch is that the I/O is the big bottleneck.
 > My parallel port is on a card, not on the motherboard, and might
 > well be particularly slow.

The ISA bus requires a 1usec hang for every I/O operation.  Sounds to
me like you're running code from the cache, and writing the results to
non-ISA memory.

-russ <nelson@crynwr.com>    http://www.crynwr.com/~nelson
Crynwr Software   | Crynwr Software sells packet driver support | PGP ok
11 Grant St.      | +1 315 268 1925 voice | Good government is a contradiction
Potsdam, NY 13676 | +1 315 268 9201 FAX   | in terms.  Ask me for details.

References:

xqcam speed figures

From: Wim Lewis <wiml@hhhh.org>

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