Hello,
We have migrated from Solr 5.4.1 to Solr 6.4.0 on Amazon EC2 and we have
a high CPU SYS usage and it drastically decreases the Solr performance.
The JVM version (java-1.8.0-openjdk-1.8.0.131-0.b11.el6_9.x86_64), the
Jetty version (9.3.14) and the OS version (CentOS 6.9) have not changed
with the Solr upgrade.
Using "strace" command we have found a lot of "clock_gettime"
(gettimeofday) calls when Solr is started.
The clocksource on Amazon VMs is "xen" and, according to this web site,
it impacts the system calls:
https://blog.packagecloud.io/eng/2017/03/08/system-calls-are-much-slower-on-ec2/
We have updated the clocksource to "tsc" and it fixes the issue.
Is there a change between Solr 5.4.1 and 6.4.0 that would trigger many
more gettimeofday calls done by the JVM ?
Elodie
Kelkoo SAS
Société par Actions Simplifiée
Au capital de € 4.168.964,30
Siège social : 158 Ter Rue du Temple 75003 Paris
425 093 069 RCS Paris
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