Re: [PATCH 4/5] futex: Avoid taking hb lock if nothing to wakeup

[Peter Zijlstra]

On Mon, Nov 25, 2013 at 06:32:55PM +0100, Thomas Gleixner wrote:
> In that context it would also be helpful to measure the overhead on
> x86 for the !empty case.

Yes, because mfence is by no means a cheap instruction on x86.
--
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/