Comment 11 for bug 579117

First, the logging does not make sense to me; in the default configuration (/etc/rsyslog.d/50-default.conf) says that what goes to /var/log/messages is a subset of what goes to /var/log/syslog.

I feel somewhat out on deep water here (I should really learn more about this), but there is a test called "cyclictest", mostly used for real-time kernels, see https://rt.wiki.kernel.org/index.php/Worstcase_Latency_Test_Scenario
I have never used that test myself, but I believe it will show you some "spikes" in latency, and it would be interesting to know the maximum values of these.