RFR: 8347434: Richer VM operations events logging

[Aleksey Shipilev]

On Fri, 10 Jan 2025 15:08:36 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> A simpler quality of diagnostics improvement. In hs_err, it is not abundantly clear if executed VM operations took safepoint or not, were nested or not. It would be good to print that out.

Example log before:


VM Operations (10 events):
Event: 0.069 Executing VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.069 Executing VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.213 Executing VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.213 Executing VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.486 Executing VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.486 Executing VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.579 Executing VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.579 Executing VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.596 Executing VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.596 Executing VM operation: HandshakeAllThreads (Deoptimize) done


...and after:


VM Operations (10 events):
Event: 0.065 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.065 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.191 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.191 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.423 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.423 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.506 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.506 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize) done
Event: 0.519 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize)
Event: 0.519 Executing non-safepoint VM operation: HandshakeAllThreads (Deoptimize) done

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PR Comment: https://git.openjdk.org/jdk/pull/23039#issuecomment-2582924941