Path: utzoo!mnetor!uunet!pcrat!rick
From: rick@pcrat.UUCP (Rick Richardson)
Newsgroups: comp.arch
Subject: Re: Curb Feelers
Message-ID: <475@pcrat.UUCP>
Date: 30 Apr 88 20:34:21 GMT
References: <7762@alice.UUCP> <418@ole.UUCP> <3216@phri.UUCP> <1574@osiris.UUCP> <505@xios.XIOS.UUCP> <4777@cup.portal.com>
Reply-To: rick@pcrat.UUCP (Rick Richardson)
Distribution: na
Organization: PC Research, Inc., Tinton Falls, NJ
Lines: 18

In article <4777@cup.portal.com> Paul_L_Schauble@cup.portal.com writes:
>All of the Honeywell (Now Honeywell-Bull) machines have percent busy meters
>for each processor. We've progressed from mechanical meters to bar graphs.
>They can be very useful for OS debugging.

Simple methods often provide valuable information.  On many occasions
I've used what I call a "Real Time Meter" to measure the average
amount of time a program spends processing interrupts.  A very simple
gadget: it consists of a milliamp meter and a (variable) resistor.
I simply arrange for any ISR's to turn on any convenient output bit
on entry, and turn the bit off on exit.  The gadget, being mechanical
and all, does the integration for you, and the readout (once calibrated)
gives a good picture of how much time is being spent processing interrupts.
-- 
		Rick Richardson, President, PC Research, Inc.

(201) 542-3734 (voice, nights)   OR     (201) 834-1378 (voice, days)
uunet!pcrat!rick (UUCP)			rick%pcrat.uucp@uunet.uu.net (INTERNET)