FILEDESC_LOCK() implementation

[John-Mark Gurney]

Kris Kennaway wrote this message on Mon, Jun 12, 2006 at 01:41 -0400:
> I fixed mutex profiling to a) not be as wrong and b) not suck so very
> much, and here is a revised profiling trace from mysql supersmack on a
> 12 cpu E4500, sorted by ratio of cnt_lock/count; filedesc lock
> contention (via FILEDESC_[UN]LOCK()) is the major mutex contention
> problem.

Should we also look at breaking down filedesc lock to have multiple
locks over the range?  I am thinking of writing a program that will
have 32 threads (sun4v) and all threads will be doing heavy i/o, and
will be even more heavily contested on FILEDESC than the supersmack
benchmark would be...

Though this doesn't solve the problem of all 32 threads trying to do
i/o on a fd in the same block though...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."