Re: [PATCH 1/2] futex: eliminate cache miss from futex_hash()

From: Peter Zijlstra
Date: Mon Jun 22 2015 - 09:55:24 EST


On Mon, Jun 22, 2015 at 03:45:10PM +0200, Rasmus Villemoes wrote:
> On Mon, Jun 22 2015, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> > Does: __aligned(sizeof(__futex_data)), work?

> Unfortunately not:

> > Because 16 might waste 8 bytes on 32bit.
>
> Yeah, wasting >= 48 bytes was the reason I didn't make it
> ____cacheline_aligned. If 8 bytes is also too much, I suppose one could
> just give the struct a tag and then use sizeof(struct futex_data).

Nah, its probably fine, just wondering if it could be done better.
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