hey question...

Will this be backported/available as an update to rhel7/centos7 as
well at some point in the "near" future??

thanks

On Thu, Aug 28, 2014 at 8:16 PM, barry Chung <barry_c_at_mail.com> wrote:
> On Tuesday, August 12, 2014 12:29:55 Alastair Scobie wrote:
>>> On 12/08/14 12:18, Kamil Dudka wrote:
>>> > On Tuesday, August 12, 2014 10:05:37 Alastair Scobie wrote:
>>> >> Whilst porting an in-house application, which uses libcurl, from RHEL6
>>> >> to RHEL7 we noticed that the time taken by libcurl to fetch a page had
>>> >> substantially increased. Even an attempt at fetching a non-existent page
>>> >> has increased from 10-20ms to around 150ms. This with just plain HTTP.
>>> >
>>> > What exactly do you mean by a non-existent page?
>>>
>>> A page for which you'll receive a 404. Ie. HTTP server address is
>>> correct, but actual page requested doesn't exist.
>>>
>>> >> Our first thought was that the API has changed in some subtle way and
>>> >> the fault must be in our code, but then we thought to try measuring the
>>> >> performance of the curl tool itself. To our surprise, we found the same
>>> >> performance disparity.
>>> >>
>>> >> Interestingly...
>>> >>
>>> >> * Adding the DNS address of the HTTP server to /etc/hosts (and
>>> >> specifying files,dns in /etc/nsswitch.conf) does not improve things
>>> >
>>> > Did you try to measure the time consumed by 'getent ahosts'?
>>>
>>> Small number of ms for both RHEL6 and RHEl7.
>>>
>>> >> * but, performance when using an IP address in the URL is fine (~
>>> >> 10-20ms) for both RHEL6 and RHEL7
>>> >
>>> > I was not able to reproduce this behavior. Is it reproducible locally?
>>>
>>> Yip, on several machines. I can ship you an strace if you like?
>>I would prefer a self-contained program that I can use to repeat the bug.
>>> (Daniel's suggestion of disabling the threaded resolver has fixed the
>>> issue for us).
>>>
>>> Cheers, Alastair
>>The problem is that either you will not receive security updates for (lib)curl
>>any more, or the threaded resolver will be re-enabled on the next update.
>>Kamil
>
> We are also hitting this while porting our software to RHEL7. Like Alastair
> mentioned, using IP address does not have the issue. wget also works fine.
>
> Kamil, you should be reproduce this by
> 1) bring up a RHEL7 minimal installation
> 2) install httpd or lighttpd
> 3) sudo tail -f /var/log/lighttpd/access.log
> 4a) while [ 1 ]; do curl http://localhost/badpage; done
> 4b) while [ 1 ]; do curl http://127.0.0.1/badpage; done
>
> There will be huge difference in the access count per second between 4a) and 4b).
>
> BTW, I uninstalled 7.29.0-19.el7 and installed 7.37.1-3.0.cf.rhel7 from
> http://curl.haxx.se/download.html but the problem still seems to exist.
>
> Thanks,
> Barry
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Received on 2014-08-29