hi,

we experienced increasingly high amounts of CPU usage on our jenkins master machine:
i made a CPU sample using visualVM (screenshot attached)
the sample shows excessive CPU-time at CipherInputStream.fill_buffer() which performs the actual read from the ssh-connection as far as i understand this.
the sample only looks like this when a build is performed on a slave. I'm pretty sure the main cause of traffic via CipherInputStream is to stream logfiles of builds or other stuff that's getting archived.

the slaves are running on
CentOS release 6.4 (Final)
[kazesberger@grzcislave32 ~]$ ssh -V
OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010

the jenkins-master has no execution-slots itself.
we are using ssh-slaves-plugin version 1.5

currently i do not have any clue whether the problem is at trilead-ssh2-jenkins or at OpenSSH. the symptom occurs on the trilead-ssh2-jenkins side.