JDK-8009120 : Fuzz instruction scheduling in HotSpot compilers
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2013-02-27
  • Updated: 2020-09-29
  • Resolved: 2013-03-05
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JDK 7 JDK 8 Other
7u181Fixed 8Fixed hs25Fixed
Related Reports
Duplicate :  
JDK-4738695 - Compilation module stress testing
Relates :  
JDK-8253765 - C2: Control randomization in StressLCM and StressGCM
Relates :  
JDK-8007898 - Incorrect optimization of Memory Barriers in Matcher::post_store_load_barrier()
Description
This improvement will greatly aid the concurrency testing.

The possible idea is:
  - LCM schedules the instructions within the basic block, choosing the schedule based on the node inputs, latency, etc; we can hijack the selection process and randomize the choice.
  - GCM selects the basic block up the dominator tree with the best latency to fit the Node in; we can hijack this and randomize the placement.
Comments
Enabling -XX:+FuzzInstructionScheduling with this patch helps to reproduce the issue in JDK-8007898.
27-02-2013