Re: [PATCH] CPU frequency display in /proc/cpuinfo

From: Avi Kivity
Date: Mon Dec 05 2005 - 11:28:25 EST


Dave Jones wrote:

I can't think of a single valid reason why a program would want
to know the MHz rating of a CPU. Given that it's a) approximate,
b) subject to change due to power management, c) completely nonsensical
across CPU vendors, and d) only one of many variables regarding CPU
performance, any program that bases any decision on the values found
by parsing that field of /proc/cpuinfo is utterly broken beyond belief.


Sometimes you need extremely low overhead time measurements, which need not be too accurate. One way to do this is to dump rdtsc measurements into some array, and later scale it using the cpu frequency.

I've done exactly this. The processes were pinned to their processors, and there was no frequency scaling in effect. It worked very well.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/