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Path: utzoo!utcsrgv!utai!uthub!thomson
From: thomson@uthub.UUCP (Brian Thomson)
Newsgroups: net.unix-wizards
Subject: Re: instrumenting cache followup and request for info
Message-ID: <173@uthub.UUCP>
Date: Tue, 7-Aug-84 11:09:09 EDT
Article-I.D.: uthub.173
Posted: Tue Aug  7 11:09:09 1984
Date-Received: Tue, 7-Aug-84 17:34:44 EDT
References: <1269@nsc.UUCP>
Organization: CSRG, University of Toronto
Lines: 14

From nsc!chuqui ...

> Our 4.2 780 is still
> running DZ's using the dma simulation code. We are getting an enormous
> number of interrupts generated (with 8 DZ boards, who wouldn't???). Each
> interrupt seems to be dropping through the Swtch process scheduler routine,
> which sets up a new process for the CPU to play with.

Are you sure you're not mistaking idle time for "setting up a new process"?
The idle loop is in the Swtch routine.  On a 4.2 780 here, I once put
25000 chars/sec out through the DZ pseudo-DMA code and had cpu to spare.
-- 
		    Brian Thomson,	    CSRI Univ. of Toronto
		    {linus,ihnp4,uw-beaver,floyd,utzoo}!utcsrgv!uthub!thomson