svn commit: r230201 - head/lib/libc/gen

[John Baldwin]

On Thursday, January 19, 2012 12:57:50 am David Xu wrote:
> rdtsc() may not work on SMP, so I have updated it to use clock_gettime 
> to get total time.
> http://people.freebsd.org/~davidxu/bench/semaphore2/ 
> <http://people.freebsd.org/%7Edavidxu/bench/semaphore2/>
> 
> Still, lfence is a lot faster than atomic lock.

http://www.freebsd.org/~jhb/patches/amd64_fence.patch

This the patch I've had for quite a while.  Can you retest with this?  You'll 
probably have to install the updated header in /usr/include as well.

-- 
John Baldwin