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Date:      Fri, 18 Apr 1997 13:00:41 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        luigi@labinfo.iet.unipi.it (Luigi Rizzo)
Cc:        dufault@hda.com, hackers@freebsd.org
Subject:   Re: video capture driver interface to file system?
Message-ID:  <199704182000.NAA02654@phaeton.artisoft.com>
In-Reply-To: <199704181044.MAA08521@labinfo.iet.unipi.it> from "Luigi Rizzo" at Apr 18, 97 12:44:39 pm

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> probably the latter :)
> 
> I have IDE disks (WD Caviar) streming files at about 3MB/s (sustained
> over about 10 minutes) with a Pentium 133 running "tv" at the same
> time. Even if the raw disk speed would go up to 10MB/s I doubt the copy
> overhead would barely slow down the process on a PPro.

For what it's worth, we heavily profiled the entire FS framework,
and by far the biggest overhead was the (~80%) time spent in the
copy in uiomove() (there was a lot of time spent waiting for the
driver to do its job, but that's not accounted against the process).


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



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