Funny, I have been considering making the same change. The 18.2 ticks per
second of the IBM PC is rather coarse. It was acceptable for slow machines
like 8088's and 80286's but is not acceptable for today's higher speeds. In
fact almost every machine I worked with since the early 1970's used either 60HZ
or 100HZ as the basic interval.
For accurate performance measurements it is also important to calibrate the
interval timer. I am thinking along the lines of using the Real Time Clock as
a standard and then measuring the interval against the RTC. On most machines,
the RTC drift is on the order of a few seconds per day or about a minute per
month.
Time drifts on this order are acceptable for determining the exact count needed
by the interval timer on a specific machine. By using a common calibration
algorithm we can more reliably compare performance results.
Also note that by calibrating the clock, we can also get a performance metric a
la Linux's BogoMips. By normalizing any performance measure against the
BogoMips, we can see the true costs/benefits of VSTa and its algorithms in a
machine independent fashion.
Now all I have to do is to implement the calibrator...:->
-- David Koogler (koogler@bedford.progress.com)Received on Tue Feb 14 05:53:33 1995
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