More dispatcher tuning for ppc32/64.  Makes a big difference for
perf/tinycc.

- run_thread_for_a_while: just clear this thread's reservation when
  starting, not all of them.

- use a different fast-cache hashing function for ppc32/64 than for
  x86/amd64.  This allows the former to use all the fast-cache entries
  rather than just 1/4 of them.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5441 a5019735-40e9-0310-863c-91ae7b9d1cf9
4 files changed