Summary:
In glibc, pthread cancellation support adds two atomic CAS operations
to each "cancellation point" syscall (see pthreads(7)). This includes
read() and write(). We can avoid that overhead by disabling pthread
cancellation at the start of the FUSE worker threads.
This saves two CAS operations (~40 ns) in the critical FUSE request
processing loop.
Reviewed By: simpkins
Differential Revision: D21469690
fbshipit-source-id: 7f28a2a8e831006351657981e901dc572c58cf48
