Path: utzoo!utgpu!cunews!bnrgate!brtph3!brchh104!brchs1!bnr.ca!rice.edu!sun-spots-request
From: mrsvr!gemed.kohli@uwm.edu (Jim Kohli)
Newsgroups: comp.sys.sun
Subject: Re: Accurate time measurements on SS1+, 3/260, etc.
Keywords: Miscellaneous
Message-ID: <941@brchh104.bnr.ca>
Date: 30 Dec 90 01:04:00 GMT
Sender: news@brchh104.bnr.ca
Organization: Sun-Spots
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Approved: Sun-Spots@rice.edu
X-Original-Date: 21 Dec 90 22:50:15 GMT
X-Refs:  Original: v9n407
X-Sun-Spots-Digest: Volume 9, Issue 411, message 8
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In article <915@brchh104.bnr.ca>, rcomr@koel.co.rmit.oz.au (Mark
Rawling) writes:
<I am trying to make some accurate timing measurements of function call
<times (user times only). It is intended to have the code monitor itself
<something like :-
<
<    ...
<    get_current_time(&start);
<    function_to_be_timed();
<    get_current_time(&stop);
<    function_time = stop - start;
<    ...
<
<The problem is that getrusage is limited to 10mS resolution (on the SS1+,
<and worse elsewhere). Thus the rusage.ru_utime.tv_usec field is always
<nn0000 micro-secs. The only thing I can see that is potentially better
<than this is "time (3V)" which returns a milliseconds field. But of
<course, this is real time and would require running single user, disabling
<interrupts, etc.

It is not unusual to do something like this:

    ...
    get_current_time(&start);
	for( i=0 ; i<1000 ; i++ ) function_to_be_timed();
    get_current_time(&stop);
    function_time = (float)(stop - start)/1000.0;
    ...

Jim Kohli
GE Medical