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SubjectRe: [PATCH] Implementation of the sendgroup() system call
On Mon, May 04, 2009 at 09:44:31AM -0400, Elad Lahav wrote:
> >My guess it's more the copies than the calls?
> It's a factor of both. This is why we also created the sendgroup()
> implementation that uses a tight loop of in-kernel calls to sendmsg()
> as a means for evaluating the cost of mode switches. It is definitely
> not negligible (exact numbers depend on the size of the group and the
> size of the payload, of course).

How much is non negligible in your case?

>
> >It sounds like you want sendfile() for UDP.
> Do you mean by having a per-recipient sendfile() call for the same
> file? Leaving the cost of the system call aside, this solution does
> not work well with the kind of real-time data that we've been working
> with (live streaming, online games). You would have to write the
> payload to the file as it is being generated and call sendfile() after
> each such write.

You can mmap the file.

-Andi

--
ak@linux.intel.com -- Speaking for myself only.


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