Linux: Tuning CFS

“Nick Piggin used ‘git bisect’ to track a lmbench regression to
the main CFS commit, leading to an interesting discussion between
Nick and Ingo Molnar. Ultimately the regression was tracked down to
the temporary configurability of the scheduler while it is tuned
for optimal performance, ‘one reason for the extra overhead is the
current tunability of CFS, but that is not fundamental, it’s caused
by the many knobs that CFS has at the moment.’ The solution,
already coded but not yet merged in the mainline kernel ‘changes
those knobs to constants, allowing the compiler to optimize the
math better and reduce code size,’ and as a result result, ‘CFS can
be faster at micro-context-switching than 2.6.22…'”

Complete
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