Re: [patch 2/3] ipc: use shifts to extract seq/idx

[Manfred Spraul]

On 05/20/2010 09:00 AM, Nick Piggin wrote:
> All the ipc ids and sequences are signed integers, so power of 2
> sequence multiplier does not work so well. Convert it to use shifts,
> which improves generated code particularly in ipc_lock/ipc_lock_check
> fast paths.
>
>    
Have you checked the asm output?
I would expect that gcc auto-optimizes constant divides by power-of-two.

--
    Manfred
--
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/