Re: [PATCH v6 5/6] MCS Lock: Restructure the MCS lock defines andlocking code into its own file

From: Ingo Molnar
Date: Fri Sep 27 2013 - 02:02:28 EST

* Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote:

> > If we prefer to optimize this a bit though, perhaps we can first move
> > the node->lock = 0 so that it gets executed after the "if (likely(prev
> > == NULL)) {}" code block and then delete "node->lock = 1" inside the
> > code block.
> I suppose we can save one single assignment. The gain is probably not
> noticeable as once we set node->next to NULL, node->locked is likely in
> local cache line and the assignment operation is cheap.

Would be nice to have this as a separate, add-on patch. Every single
instruction removal that has no downside is an upside!

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