RE: Regression in reading /proc/stat in the newer kernels withlarge SMP and NUMA configurations

[Eric Dumazet]

Le vendredi 14 octobre 2011 Ã 14:36 +0100, Seger, Mark a Ãcrit :

> For me the easiest reproducer, which admittedly doesn't show any
> deeper analysis, is to just run "cat /proc/stat>/dev/null" in a loop
> and time it.

OK, but you already provided a global number.

We would like to check where in kernel cpu time is consumed.
Maybe something really obvious could pop out.

"perf" is provided in kernel sources, and really is a piece of cake.

cd tools/perf ; make 



2x4x2 means : Two sockets, 4 cores per physical package, 2 threads per
core.



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