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Re: Curl/LibCurl compiled on OS X without --disable-ipv6 is really slow

From: Shantonu Sen <>
Date: Mon, 22 Dec 2003 09:53:28 -0800

On Dec 19, 2003, at 2:10 AM, Jacob Swed wrote:

> The library version being used is 7.11.0-20031217. Compiled under OS X
> 10.2.8.
> We have not investigated the why, but have determined that if
> curl/libcurl is complied on OS X without the --disable-ipv6 option
> performance is severely and noticeably degraded. curl/libcurl takes an
> extremely long time resolving the host or host IP. Compiling with the
> --disable-ipv6 option alleviates the delays entirely. Incidentally,
> this occurs when run on vanilla installations of OS 10.1, 10.2 and
> 10.3.

Each one of those releases has had signifcantly different levels of
support of both IPv6 in general, and IPv6 hostname resolution in
specific. I don't think 10.1 shipped with any IPv6 support.

What does "without --disable-ipv6" mean? Was IPv6 autodetected? I would
not expect this on 10.1, for instance.

Can you provide a test case (perhaps a specific hostname you were using
and profiling information pointing at getaddrinfo if possible). If you
can, I can take a look at this in the new year and see if Apple has
existing problem reports relating to resolution speed and ask for
improvements for the next release.

Mac OS X should be hitting lookupd as a cache for all hostname
resolution, so I would not expect a significant amount of network delay
contributing to this issue after an initial lookup. Maybe that's not


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Received on 2003-12-22