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

Ingo Molnar
2013-09-27T06:02:20Z

* Tim Chen <tim.c.chen@linux.intel.com> 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!

You can add a comment that explains it.

Thanks,

Ingo