RFR: 8179040: Avoid Ticks::now calls when EventClassLoad is not enabled
markus.gronlund at oracle.com
Tue Apr 25 13:37:18 UTC 2017
Looks good, thanks for fixing this.
From: Claes Redestad
Sent: den 25 april 2017 15:21
To: hotspot-runtime-dev at openjdk.java.net
Subject:  RFR: 8179040: Avoid Ticks::now calls when EventClassLoad is not enabled
this patch removes calling Ticks::now when EventClassLoad isn't enabled, which has an effect on class loading performance:
When tracing isn't enabled trace/tracing.hpp has dummy implementations which are easily optimized away by a compiler, which I've verified happens on linux OpenJDK builds with tracing disabled.
On builds with tracing enabled then the changes means the call to get the time only happen if the event is enabled, which achieves the sought after startup optimization.
More information about the hotspot-runtime-dev