Re: Re-tune x86 uaccess code for PREEMPT_VOLUNTARY

[H. Peter Anvin]

On 08/09/2013 10:55 PM, Mike Galbraith wrote:
>>
>> Now, here is a bigger question: shouldn't we be deprecating/getting rid
>> of PREEMPT_VOUNTARY in favor of PREEMPT?
> 
> I sure hope not, PREEMPT munches throughput.  If you need PREEMPT, seems
> to me what you _really_ need is PREEMPT_RT (the real deal), so
> eventually depreciating PREEMPT makes more sense to me.
> 

Do you have any quantification of "munches throughput?"  It seems odd
that it would be worse than polling for preempt all over the kernel, but
perhaps the additional locking is what costs.

	-hpa


--
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/