[jvm] The PerfDisableSharedMem option

[supercaracal]

Hi,

I am writing to share trouble information related to Mackerel JVM plugin.

We cannot use the plugin when we use the latest Apache Solr 8.2.0 (2019-09). This is related the following reports.

• a Hatena Bookmark comment (Japanese)
• JVM statistics cause garbage collection pauses
• hsperfdata causing long GC/safepoint times: Don't use mmap?
• Cassandra - JVM Tooling
• Why Java performance utilities like jps no longer work in DSE 5.0+
• Solr wiki > ShawnHeisey > GC Tuning for Solr > G1 (Garbage First) Collector > Current Experiments
• JVM Agent not compatible with -XX:+PerfDisableSharedMem jolokia/jolokia#198

The Solr is specifing the JVM option -XX:+PerfDisableSharedMem as default at the follow.

https://github.com/apache/lucene-solr/blob/e45e8127d5c17af4e4b87a0a4eaf0afaf4f9ff4b/solr/bin/solr#L2027

I can't make up my mind which enable or disable the JVM option yet.

• -XX:+PerfDisableSharedMem
• -XX:-PerfDisableSharedMem

Maybe we will plan to use alternative plugin. (e.g. mackerel-plugin-solrjvm)

I'd say that middlewares running on JVM and using -XX:+PerfDisableSharedMem option might will be increase.

P.S. I will close this issue later.

[astj]

Thank you for detailed information! We haven't recognized such problems.
Maybe we should mention such cases in README, at least.