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PerfectSlayer
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Jan 6, 2023
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What Does This Do
Relies on an assumption that the initial part of the vmId from
ManagementFactoryis our process id.This is true for all JVMs based on OpenJDK, but may not be true for other JVMs that don't follow this convention:
https://github.com/openjdk/jdk/blob/jdk8-b120/jdk/src/share/classes/sun/management/VMManagementImpl.java#L145
Note that JVMs after Java8 will continue to use the standard
ProcessHandle.current().pid()APIMotivation
PR #4397 added the process-id to all root spans, which means that the process-id is now requested as part of building the tracer in
premain. Unfortunately the JNR/POSIX layer which is used for Java8 only takes some time to initialize, and this leads to a noticeable increase in startup time.On my M1 mac the JNR/POSIX approach takes 0.5 seconds, whereas using
ManagementFactorytakes 0.03 seconds.