Callgrind new feature: count global bus lock events "Ge"

Callgrind new feature: count global bus lock events "Ge"

To count global bus lock events, use "--collect-bus=yes".
For x86, this will count the number of executed instructions
with a lock prefix; for architectures with LL/SC, this will
count the number of executed SC instructions.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11167