Re: [PATCH] http: use curl's tcp keepalive if available
Jeff King <peff@peff.net> wrote:
Show 29 quoted lines
> On Mon, Oct 14, 2013 at 11:38:39PM +0000, Eric Wong wrote:
>
> > I wanted it to work as older curl first (since I noticed this
> > on an old server). But your patch on top of mine looks reasonable,
> > thanks.
>
> Makes sense. Here it is with a real commit message (on top of the
> ew/keepalive topic).
>
> -- >8 --
> Subject: http: use curl's tcp keepalive if available
>
> Commit a15d069 taught git to use curl's SOCKOPTFUNCTION hook
> to turn on TCP keepalives. However, modern versions of curl
> have a TCP_KEEPALIVE option, which can do this for us. As an
> added bonus, the curl code knows how to turn on keepalive
> for a much wider variety of platforms. The only downside to
> using this option is that not everybody has a new enough curl.
> Let's split our keepalive options into three conditionals:
>
> 1. With curl 7.25.0 and newer, we rely on curl to do it
> right.
>
> 2. With older curl that still knows SOCKOPTFUNCTION, we
> use the code from a15d069.
>
> 3. Otherwise, we are out of luck, and the call is a no-op.
>
> Signed-off-by: Jeff King <peff@peff.net>
Thanks.
Tested-by: Eric Wong <normalperson@yhbt.net>
on curl 7.21.0 and 7.26.0, confirmed via strace:
setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
I can also confirm 7.26.0 adds:
setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, [60], 4) = 0
setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, [60], 4) = 0
to the strace on Linux.
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> ---
> Given the #ifdefs in curl's keepalive code, I suspect we may see build
> problems for people in case 2 on some systems, with or without my patch.
> I think this patch is a strict improvement, though; if they have a new
> enough curl, they will not even look at the case 2 code. And if they do
> not, our previous options were:
>
> a. Add platform-specific code for them.
>
> b. Tell them they are out of luck, and add an #ifdef to push them into
> case 3.
Case 2 works fine on my Debian Squeeze system.
> Now we have an extra option:
>
> c. Tell them to upgrade curl. :)
Yes, I keep forgetting I still have a Debian Squeeze machine :x