Re: question about splice performance

[Jeff Garzik]

Francis Moreau wrote:
> Hi,
>
> I did a really basic benchmark and was suprise about the results.
>
> $ echo 3 > /proc/sys/vm/drop_caches
> $ time  splice-cp  vmlinux /tmp/vmlinux
>
> real    0m10.158s
> user    0m0.002s
> sys     0m0.401s
>
> $ echo 3 > /proc/sys/vm/drop_caches
> $ time  cp  vmlinux /tmp/vmlinux
>
> real    0m10.590s
> user    0m0.017s
> sys     0m0.459s
>
>
> I was expecting splice-cp case to be faster.
>
> Could someone enlight me ?

If you drop caches you are not measuring splice speed.

Use ramfs for your tests (guarantees data is in cache) instead.

	Jeff



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