Re: [PATCH 2/2] perf_counter: optimize context switch betweenidentical inherited contexts

From: Paul Mackerras
Date: Fri May 22 2009 - 06:08:53 EST


Peter Zijlstra writes:

> Ah, should I read this as 'n' lmbench instances on a single cpu? So that
> we get multiple inheritance sets mixed and have to switch between them?

No, it's one lat_ctx instance, which creates N processes connected in
a ring with pipes, and passes a token around some number of times and
measures the overall time to do that. It subtracts off the time it
takes to do all the pipe reads and writes in a single process to get
an estimate of how much the context switches are costing.

Paul.
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