Re: Microstate Accounting for 2.6.11

From: Andi Kleen
Date: Fri Mar 11 2005 - 02:15:38 EST


Andrew Morton <akpm@xxxxxxxx> writes:

> Why does the kernel need this feature?
>
> Have you any numbers on the overhead?

It does RDTSC and lots of complicated stuff twice for each system call.
On P4 this will be extremly slow (> 1000cycles combined)
It is pretty unlikely that whatever it does justifies this extreme
overhead in a critical fast path.

-Andi
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