Re: Performance counter API review was [patch] PerformanceCounters for Linux, v3

[Peter Zijlstra]

On Wed, 2009-02-04 at 21:47 +1100, Paul Mackerras wrote:
> Peter Zijlstra writes:
> 
> > How is smp_call_function() going to help here? You still need to pull
> > all that data through that one FD. That's a cacheline bounce fest.
> 
> Well, let's put this into perspective.  We would be collecting 8 bytes
> of data from each CPU.  Hardly a "cacheline bounce fest". :)

Ah, I was thinking more of the event triggered profiling, like NMI time,
cachemiss or pagefault profiling.

In those cases you'd get a continuous stream of data for each cpu, at
possibly quite high speeds.

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