Messages in this thread | | | Date | Thu, 18 Aug 2005 20:06:39 +0900 | From | Hiro Yoshioka <> | Subject | Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll() |
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On 16 Aug 2005 15:15:35 +0200, Andi Kleen <ak@suse.de> wrote: > However it disables preemption, which especially for bigger > copies will probably make the low latency people unhappy.
In the copy loop, +#ifdef CONFIG_PREEMPT + if ( (i%64)==0 ) { + MMX_RESTORE; + MMX_SAVE; + }; +#endif
It costs several hundred clocks (wow) every 4KB copy.
It kills throughput but it makes the low latency people smile.
So I make two APIs. __copy_user_zeroing_nocache() __copy_user_zeroing_inatomic_nocache()
The former is a low latency version and the other is a throughput version.
What do you think?
Regards, Hiro
-- Hiro Yoshioka mailto:hyoshiok at miraclelinux.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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