Re: CONFIG_PREEMPT and server workloads

[Andrea Arcangeli]

On Thu, Mar 18, 2004 at 12:48:50PM -0500, Robert Love wrote:
> On Thu, 2004-03-18 at 09:51, Andrea Arcangeli wrote:
> 
> > the counter is definitely not optimized away, see:
> 
> This is because of work Dave Miller and Ingo did - irq count, softirq
> count, and lock count (when PREEMPT=y) are unified into preempt_count. 
> 
> So it is intended.
> 
> The unification makes things cleaner and simpler, using one value in
> place of three and one interface and concept in place of many others. 
> It also gives us a single simple thing to check for an overall notion of
> "atomicity", which is what makes debugging so nice.

You're right, I didn't notice the other counters disappeared.  Those
counter existed anyways w/o preempt too, so it would been superflous
with preempt=y to do the accounting in two places. So this is zerocost
with preempt=n and I was wrong claiming superflous preempt leftovers.
-
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/