apr-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From <...@apache.org>
Subject Re: APR_TCP_NOPUSH
Date Fri, 13 Dec 2002 18:12:17 GMT
On Fri, 13 Dec 2002, Aaron Bannert wrote:

> It looks to me like it's used in conjunction with sendfile
> on Linux, and is probably useful for preventing slow starts
> on big bursts of data (like a response). I suspect it is
> especially useful when each header in the hdtr->headers iovec
> is not going to fill a full packet. (Is this thing anything
> other than the opposite of TCP_NODELAY?)
>
> It is one of those things that only helps if you have it and
> doesn't hurt if you don't.

The web server doesn't use it to stop slow starts on big bursts of data,
because the concept is completely non-portable.  That makes the whole
thing ludicrous to have in a portable run-time.  If the app tries to take
advantage of APR_TCP_NODELAY, and they test on Linux or FreeBSD, it will
do exactly  what they expect.  However, if they test on _any_ other
platform, it won't.

So, I continue to wonder, how is it useful to have this in a _portable_
run-time, when the concept isn't at all portable?

Ryan

>
> -aaron
>
>
> On Friday, December 13, 2002, at 09:11  AM, <rbb@apache.org> wrote:
>
> >
> > This concept is not portable at all as far as I know, so why do we
> > expose
> > it in our API?  My understanding of TCP_NOPUSH is that it is how linux
> > implements sendfile.  If that is the case, then it should be removed
> > from
> > our public API, and we should just use it behind the scenes.
> >
> > If that isn't the case, then can somebody please explain how an
> > application that uses APR_TCP_NOPUSH is at all portable?  Once that
> > flag
> > is used, the application will behave differently on many platforms.
> >
> > I would like to remove that macro later this weekend, so please let me
> > know if that will be an issue.
>
>


Mime
View raw message