Comment 24 for bug 1058864

I'm running 12.04 so I gave the 3.4 kernel a try ( http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.4-precise/ ). It appears that the performance is about the same, if not worse, with 3.4.

Here are the results:
mutex
 1 thread real 0m 0.515s user 0m 0.508s sys 0m 0.004s
 2 threads real 0m 4.305s user 0m 4.848s sys 0m 3.728s
 4 threads real 0m12.149s user 0m 9.553s sys 0m33.058s
 8 threads real 0m23.016s user 0m15.909s sys 1m15.709s
16 threads real 0m54.892s user 0m36.570s sys 3m 2.347s

benaphore
 1 thread real 0m 0.319s user 0m 0.316s sys 0m 0.000s
 2 threads real 0m 6.692s user 0m 6.880s sys 0m 5.824s
 4 threads real 0m21.479s user 0m15.269s sys 0m59.448s
 8 threads real 0m43.105s user 0m26.278s sys 2m25.581s
16 threads real 1m22.735s user 0m55.827s sys 4m34.185s

mutex2
 1 thread real 0m 0.322s user 0m 0.316s sys 0m 0.004s
 2 threads real 0m 0.843s user 0m 1.088s sys 0m 0.564s
 4 threads real 0m 2.323s user 0m 3.516s sys 0m 5.648s
 8 threads real 0m 4.184s user 0m 5.576s sys 0m11.049s
16 threads real 0m 8.070s user 0m10.841s sys 0m21.253s