Re: [PATCH [RT] 10/14] adjust pi_lock usage in wakeup

From: Steven Rostedt
Date: Thu Feb 21 2008 - 11:49:28 EST



On Thu, 21 Feb 2008, Gregory Haskins wrote:

> From: Peter W.Morreale <pmorreale@xxxxxxxxxx>
>
> In wakeup_next_waiter(), we take the pi_lock, and then find out whether
> we have another waiter to add to the pending owner. We can reduce
> contention on the pi_lock for the pending owner if we first obtain the
> pointer to the next waiter outside of the pi_lock.
>
> This patch adds a measureable increase in throughput.

I see how this may decrease contention (slightly less time in holding the
pi_lock). But, please, when stating something like: "adds a measurable
increase in throughput", show the benchmark numbers.

-- Steve

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