Question about memcpy

[bing zhu]

I‘m trying to write a simple fs in user space,if memcpy is slower than
kernel , i think it's unfair,as for only cpu for my task,
it's a bit of arbitrary ，i just want my task not interrupted during a
specific time is that possible ?

2018-07-12 22:53 GMT+08:00 Greg KH <greg at kroah.com>:

> A: http://en.wikipedia.org/wiki/Top_post
> Q: Were do I find info about this thing called top-posting?
> A: Because it messes up the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?
>
> A: No.
> Q: Should I include quotations after my reply?
>
> 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
>
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