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From: tdonahue@bbn.com (Tim Donahue)
Newsgroups: comp.arch
Subject: Re: reliable/reproduceable benchmarks on SGI MIPS box
Message-ID: <61843@bbn.BBN.COM>
Date: 3 Jan 91 14:54:53 GMT
References: <11737@alice.att.com> <44383@mips.mips.COM> <1991Jan3.035143.18865@noose.ecn.purdue.edu>
Sender: news@bbn.com
Reply-To: tdonahue@bbn.com (Tim Donahue)
Organization: BBN Advanced Computers, Inc.
Lines: 36
In-reply-to: 3ksnn64@cidmac.ecn.purdue.edu (Joe Cychosz)

In article <1991Jan3.035143.18865@noose.ecn.purdue.edu>, 3ksnn64@cidmac (Joe Cychosz) writes:
>In article <11737@alice.att.com> andrew@alice.att.com (Andrew Hume) writes:
>>
>> <stuff about timer resolution deleted>
>> ...
>
>>/* ----	second - Return user CPU time in seconds. ---------------------	*/
>/*									*/
>/*	Runction to return the elapse CPU time in seconds.  To properly	*/
>/*	compute the elapse CPU time, the function should be called	*/
>/*	twice, once in the beginning to get the initial CPU time, and	*/
>/*	a second time to get the ending time.  The elapse time is then	*/
>/*	the computed difference between the two times.			*/
>/*	between the two times.						*/
>/*									*/
>/*									*/
>/*	machine			low-res	  hi-res			*/
>/*     ...
>/*	BBN Butterfly TC-2000	  100Hz		

The TC2000 does indeed include a high-resolution clock.  This 32-bit
clock has an resolution of 1 microsecond and is synchronized by hardware
among all processors in the system.  Call getusecclock() under nX or
pSOS+m to obtain the value of this clock.

The nX and pSOS operating systems also maintain a 64-bit software clock
whose low order bits are formed by the 32-bit microsecond hardware
clock.  To obtain the value of this clock, use get64bitclock().

Finally, two microsecond-resolution interrupting timers are available
under pSOS+m.  These timers compare the programmed value with the value
of the microsecond clock.  When the microsecond clock is later or equal,
interrupts are delivered to the CPU.

Cheers,
Tim