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Re: Difference in curl performance between RHEL6 and RHEL7

From: Alastair Scobie <ascobie_at_ed.ac.uk>
Date: Tue, 12 Aug 2014 12:23:59 +0100

On 12/08/14 10:19, Daniel Stenberg wrote:
> On Tue, 12 Aug 2014, Alastair Scobie wrote:
>
>> We did notice that when using DNS names in the URL, curl forks off a
>> process to do the name lookup and then poll()s. There's no such fork
>> when using an IP address in the URL. The poll() timesout after a
>> period of time - we suspect this is the cause of the delay.
>
>> (FYI - RHEL6 curl is 7.19, RHEL7 curl is 7.29)
>
> I believe this is simply because Redhat switched their build to the
> threaded resolver and in 7.29.0 we switched some libcurl internals which
> made us have that performance issue. I think this problem is solved in a
> more recent libcurl version.

Thanks! Rebuilding curl without the threaded resolver enabled has fixed
the problem. Not a good long term solution, but will tide us over until
the more recent libcurl version hits RHEL 7.

Alastair

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Received on 2014-08-12