Obviously, going from 1.509.4 to 1.554.3 is a pretty big jump that included
lots and lots of changes. However, the fact that the singular act of
downgrading that library got us back to our prior build times is a big
smoking gun to me.

> I wonder if something changed upstream...

>From the upstream release notes:
> 
> build217, 2013-06-03:
> 
> - Support for SSH agent based authentication.
> 
> build216, 2013-03-04:
> 
> - Support of unencrypted entries in the known_hosts file.
> - Improved timeout handling.
> BTW you are using /dev/./urandom as an entropy source for the JVM?

Nope. Should we?

  -- Dean


From:  Stephen Connolly <[email protected]>
Reply-To:  "[email protected]" <[email protected]>
Date:  Tuesday, July 29, 2014 at 2:16 PM
To:  "[email protected]" <[email protected]>
Subject:  Re: SSH slave performance degradation

> * KK's changes to window sizes should have *increased* performance
> * My connection bug fixes were surgical IIRC
> * Nicolas's merge of upstream seems to include an EOL change, so hard to see
> what changed there with the Github diff tool:
> https://github.com/jenkinsci/trilead-ssh2/compare/trilead-ssh2-build214-jenkin
> s-3...trilead-ssh2-build217-jenkins-5
> 
> I wonder if something changed upstream...
> 
> BTW you are using /dev/./urandom as an entropy source for the JVM?
> 
> 
> On 29 July 2014 19:51, Dean Yu <[email protected]> wrote:
>> Hi folks,
>>   We just upgraded our cluster from 1.509.4 to 1.554.3, and discovered a
>> significant increase in our build times. Builds that typically took ~50 to
>> complete started taking ~90 minutes to finish, sometimes spiking to 2 hours.
>> While researching, we found this JIRA[1] which reported that downgrading the
>> trilead-ssh2 jar solved the performance issues.
>>   While this ticket talks specifically artifact downloads, we see that our
>> builds as a whole were slower.
>>   The trilead-ssh2 dependency version was updated by [2], so it was
>> introduced into 1.536, show would only have made it to LTS with 1.554.1 in
>> April.
>>   Looking at the trilead-ssh2 repo[3], it looks like there were a small set
>> of changes:
>>    - changes by ndeloof to merge a newer upstream (build214 to build217)
>>    - changes by stephenc to fix connection bugs
>>    - changes by kohsuke to support package window sizes
>> 
>>   Anyone have thoughts on the likely culprit? Given the severity of the
>> performance hit we took, I'm surprised that more people haven't reported
>> this.
>> 
>>   -- Dean
>> 
>> [1] https://issues.jenkins-ci.org/browse/JENKINS-20550
>> [2] 
>> https://github.com/jenkinsci/jenkins/commit/bb265c5e95b0fe39128720b9039142369
>> 62db41b
>> [3] https://github.com/jenkinsci/trilead-ssh2/commits/master
>> 
>> 
>> 
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