timing loops -> how to calibrate

Paul Barton-Davis (pbd@Op.Net)
Tue, 14 Jul 1998 10:38:00 -0400

Whats the easiest way of converting something like:

for (i = 0; i < 50000; i++);

into:

for (i = 0; i < 4; i++) {
tenmicrosecs();
}

Should I just write a test loop something like:

now = jiffies;
for (i = 0; i < 1000000; i++);
usecs_per_thousand_iterations = (jiffies - now/1000)/10000;

Does such a calibration already exist in the kernel, and if so, how do
I use it ? I want to alter some driver code from using
CPU-speed-dependent timing loops to ones based on fixed real times.

--p

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