Re: Patch: fix lock contention for HASHHDR.mutex

> > This patch affects header files. By any chance didn't you forget to
> > run `make clean` after applying it? As we discussed above, when you
> > change .h files autotools doesn't rebuild dependent .c files:
> >
> 
> Yes, actually i always compile using "make clean;make -j20; make
> install" If you want i will run it again may be today or tomorrow and
> post the result.
> 
> 

Most likely HASHHDR.mutex is not only bottleneck in your case so my
patch doesn't help much. Unfortunately I don't have access to any
POWER8 server so I can't investigate this issue. I suggest to use a
gettimeofday trick I described in a first message of this thread. Its
time consuming but it gives a clear understanding which code is keeping
a lock.