sync: replace Mutex benchmarks For both contended and uncontended case:  - support arbitrary number of cpus (not just 2)  - dynamic load balancing (improves stability)  - periodic execution of Gosched() to work around non-preemptiviness For uncontended case eliminates possible false-sharing. For contended case includes additional variation with some amount of local work between mutex operations.
sync: replace Mutex benchmarks
For both contended and uncontended case:
 - support arbitrary number of cpus (not just 2)
 - dynamic load balancing (improves stability)
 - periodic execution of Gosched() to work around non-preemptiviness
For uncontended case eliminates possible false-sharing.
For contended case includes additional variation with some
amount of local work between mutex operations.

R=r, rsc
CC=golang-dev
http://codereview.appspot.com/4634093

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go