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From: friesen@psivax.UUCP (Stanley Friesen)
Newsgroups: net.unix-wizards
Subject: Re: 4.2 scheduler
Message-ID: <882@psivax.UUCP>
Date: Mon, 2-Dec-85 11:58:57 EST
Article-I.D.: psivax.882
Posted: Mon Dec  2 11:58:57 1985
Date-Received: Thu, 5-Dec-85 04:48:22 EST
References: <1360@wanginst.UUCP> <879@psivax.UUCP> <3043@sun.uucp>
Reply-To: friesen@psivax.UUCP (Stanley Friesen)
Distribution: net
Organization: Pacesetter Systems Inc., Sylmar, CA
Lines: 27

In article <3043@sun.uucp> guy@sun.uucp (Guy Harris) writes:
>
>> The net result is that a 4.2 system spends 30 to 50% of its time in the
>> kernel(verify this by running vmstat)!! This is quite high.
>
>Well, it *can* spend that much time in the kernel, depending on what you're
>doing.  30 to 50% isn't *that* high  ...

	Well, I  consider 30% to be reasonable, but I find 50% and up
to be excessive, after all the machine is really there to execute
*user* code, not the kernal!

> the paper Berkeley put out on 4.2/4.3
>performance tuning indicated that 4.1 spent about 45% of its time in the
>kernel, 4.2 spent about 55% of its time there, and that they'd cut it back
>to 45% with their tuning.
>
	Actually, on our system I noticed a greater change. Under 4.1
with a moderate load the system time averaged about 35%, under 4.2 it
jumped the the cited 55% value.

-- 

				Sarima (Stanley Friesen)

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