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From: yodaiken@fsmlabs.com
To: "Richard B. Johnson" <root@chaos.analogic.com>
Cc: Mark Hounschell <markh@compro.net>,
	"Wessler, Siegfried" <Siegfried.Wessler@de.hbm.com>,
	"'linux-kernel@vger.kernel.org'" <linux-kernel@vger.kernel.org>
Subject: Re: interrupt latency
Date: Tue, 27 Aug 2002 13:54:01 -0600	[thread overview]
Message-ID: <20020827135400.A31990@hq.fsmlabs.com> (raw)
In-Reply-To: <Pine.LNX.3.95.1020827135107.10631A-100000@chaos.analogic.com>; from root@chaos.analogic.com on Tue, Aug 27, 2002 at 02:01:43PM -0400

On Tue, Aug 27, 2002 at 02:01:43PM -0400, Richard B. Johnson wrote:
> This cannot be. A stock kernel-2.4.18, running a 133 MHz AMD-SC520,
> (like a i586) with a 33 MHz bus, handles interrupts off IRQ7 (the lowest
> priority), from the 'printer port' at well over 75,000 per second without
> skipping a beat or missing an edge. This means that latency is at least
> as good as 1/57,000 sec = 0.013 microseconds.

Assuming you mean 75,000 then ... 
Thats 0.013 MILLISECONDS which is 13 microseconds and its not likely.
I bet that your data source drops data or looks at some handshake
pins on the parallel connect.

-- 
---------------------------------------------------------
Victor Yodaiken 
Finite State Machine Labs: The RTLinux Company.
 www.fsmlabs.com  www.rtlinux.com


  reply	other threads:[~2002-08-27 19:51 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-08-27  9:58 Wessler, Siegfried
2002-08-27 14:11 ` Stephen Samuel
2002-08-27 17:16   ` Robert Schwebel
2002-08-27 21:44     ` Stephen Samuel
2002-08-27 17:41 ` Mark Hounschell
2002-08-27 18:01   ` Richard B. Johnson
2002-08-27 19:54     ` yodaiken [this message]
2002-08-27 20:44       ` Richard B. Johnson
2002-08-27 20:56         ` yodaiken
2002-08-27 22:47           ` Rogier Wolff
2002-08-28 12:18           ` Richard B. Johnson
2002-08-28 13:41             ` yodaiken
2002-08-28 14:25               ` Jonathan Lundell
2002-08-28 13:53             ` yodaiken
2002-08-28 15:02               ` Richard B. Johnson
2002-08-28 15:19                 ` yodaiken
2002-08-28 15:31                 ` Alan Cox
2002-08-28 15:37                   ` Richard B. Johnson
2002-08-28 16:53                   ` Randy.Dunlap
2002-08-28 12:42         ` Pavel Machek
2002-08-27 18:05 ` Dag Nygren
2002-10-30 23:50 Keith Adamson

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