Re: [PATCH 07/13] block: avoid indirect calls to enter cfq io scheduler

From: Nikanth K
Date: Tue May 26 2009 - 05:02:39 EST


On Mon, May 25, 2009 at 1:00 PM, Jens Axboe <jens.axboe@xxxxxxxxxx> wrote:
>
> They can be expensive, since CPUs generally do not branch predict
> well for them.
>

Cant gcc take care of this? Comparing a pointer and then calling the
function directly without using the pointer! Wont this increase the
text size of the kernel and possibly degrade performance? Do you have
any measurement of the improvement? Is this kind of optimization being
used elsewhere?

Thanks
Nikanth
--
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/