Question about memcpy

[Greg KH]

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http://daringfireball.net/2007/07/on_top


On Thu, Jul 12, 2018 at 10:27:37PM +0800, bing zhu wrote:
> as for memcpy ,kernel is faster than user ,might because schedule ,can i try to
> make user as fast as kernel ?

You can bind a specific CPU to your userspace task, and have it only run
that program and not get interupted at all for anything.  That would
make it as fast as the kernel runs.  Lots of people do that in high
frequency trading as they don't want the CPU to get in the way of their
work or response times to the network.

But without doing fancy tricks like that, no.  Think about what an
operating system does.  It's job is to schedule things that need to be
done behind the back of your program.  Otherwise there's no need for it,
right?

good luck!

greg k-h