Re: [PATCH v5 0/6] rwsem: performance optimizations

[Davidlohr Bueso]

On Tue, 2013-09-24 at 15:22 -0700, Tim Chen wrote:
> We have incorporated various suggestions from Ingo for version 5 of this patchset
> and will like to have it merged if there are no objections.
> 
> In this patchset, we introduce two categories of optimizations to read
> write semaphore.  The first four patches from Alex Shi reduce cache bouncing of the
> sem->count field by doing a pre-read of the sem->count and avoid cmpxchg
> if possible.
> 
> The last two patches introduce similar optimistic spinning logic as
> the mutex code for the writer lock acquisition of rwsem.

Right. We address the general 'mutexes out perform writer-rwsems'
situations that has been seen in more than one case. Users now need not
worry about performance issues when choosing between these two locking
mechanisms.

Thanks,
Davidlohr


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/