JCStress 0.6

[Aleksey Shipilev]

Hi

JCStress 0.6 is released and available at Maven Central. This is useful for those who depend on 
JCStress as the Maven dependency. We have not released for a while, and so the release comes with 
many changes. This version should be compatible with any existing tests, but it should run the large 
suites much faster.

Changes include:

  *) Better hook-ups to OSes:
   - Use taskset to contain forked JVMs to preselected CPUs

  *) Better hook-ups to JVMs:
   - 7902768: jcstress should support -XX:+StressIGVN
   - 7902599: jcstress deopt rework: favor deopt-all, once per test
   - 7902726: jcstress Whitebox hooks fail on JDK 8
   - 7902725: jcstress Whitebox hooks fail on recent JDKs

  *) Test code-generation improvements:
   - Make sure methods are not accidentally polymorphic
   - Remove trap subclasses in favor of generated/accessed fields in Result and State
   - Optimize @Result hashcode to handle {0,1} efficiently
   - Lift Result and State arrays to synthetic code in order to dodge runtime typechecks
   - Micro-optimize jcstress_updateHolder stubs
   - Micro-optimize jcstress_consume stubs
   - Optimize StateHolder for footprint and performance
   - Start with minStride right away

  *) Configuration improvements:
   - 7902767: jcstress should trim down the default heap size based on total CPU count
   - 7902475: Shrink jcstress configurations
   - Runs fail with low CPU counts due to "IllegalStateException: Cannot acquire enough threads"
   - More manageable spinloop styles

  *) UX improvements
   - 7902354: jcstress should remove jcstress*stdout/stderr files
   - 7902630: jcstress: noisy progress indicator with non-interactive output
   - 7902598: jcstress should use buffered input/output streams
   - Faster @Contended startup tests
   - Do not allow to request more than physical number of CPUs
   - Human-readable sample rate measurement
   - Bump max timeout delay to 10x the normal time
   - Make "sanity" even faster: coarser VMs, shallower strides, near-zero test time

Enjoy!

-- 
Thanks,
-Aleksey