Re: [hybi] frame length encoding

On Sat, Aug 21, 2010 at 8:23 PM, Shelby Moore <shelby@coolpage.com> wrote:

> > On Sat, 2010-08-21 at 16:59 -0400, John Tamplin wrote:
> >> On Sat, Aug 21, 2010 at 4:57 PM, Shelby Moore <shelby@coolpage.com>
> >> wrote:
> >
> >>          Can you simply rewrite
> >>         one sector on disk and the memory manager remaps?
> >>
> >>
> >> I haven't tried it personally, but I would suspect you could use
> >> TCP_CORK, write a header, use sendfile to send a chunk of the file to
> >> finish the frame, uncork, repeat until done.  I don't think there
> >> would be any extra copying involved here, but you can't just issue the
> >> sendfile and go on to the next message, you need some thread that will
> >> queue up the next frame when it is ready.
> >
> > That is correct (and I have done this personally), you need multiple
> > calls of the ZC API interleaved with the write of the chunk header.
> > There is no copying of the data through the CPU just because it requires
> > multiple calls. And there is no reason you couldn't implement some kind
> > of writev() like API that lets you interleave copied and zero-copied
> > data.
> >
> > And yes, multiple calls are more overhead than 1 call. but at 1 per 4GB,
> > it really is inconsequential.
>
> That is an extremely technical solution applicable to experienced
> sysadmins.
>
> But WebSockets is supposed to be used also by web programming amateurs.
> It is much easier for them to issue a single sendFile() call from PHP,
> Perl, Ruby, etc., without all the fuss and low-level network stack API
> synchronization.
>

No, that (amateur programmers) is not a requirement currently as I
understand things.
The expectation is that we develop the minimal featureset necessary to
ensure a robust and hopefully efficient transport.
There are different perspectives about what that featureset need be assuming
competent professional programmers, and that is how you should be looking it
it!
-=R

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