Summary

Obsolete the following VM product options due to removal of corresponding functionality:

• ParallelOldDeadWoodLimiterMean
• ParallelOldDeadWoodLimiterStdDev

Problem

In a Parallel GC full collection, MarkSweepDeadRatio is used together with a normal distribution constructed from ParallelOldDeadWoodLimiterMean and ParallelOldDeadWoodLimiterStdDev to calculate how much space the garbage collection is allowed to keep not compacted.

This is a different approach compared to Serial GC and G1 GC. Using MarkSweepDeadRatio results in different amounts of allowed waste depending on the collector. This makes this aspect of Parallel GC full collection behavior hard to predict and understand in addition to an increase in code complexity without any substantial gain.

Solution

Remove the functionality and obsolete the following VM product options, without any deprecation period:

• ParallelOldDeadWoodLimiterMean
• ParallelOldDeadWoodLimiterStdDev

Specification

Removing the following flags:

  product(size_t, ParallelOldDeadWoodLimiterMean, 50,                       \
          "The mean used by the parallel compact dead wood "                \
          "limiter (a number between 0-100)")                               \
          range(0, 100)                                                     \
                                                                            \
  product(size_t, ParallelOldDeadWoodLimiterStdDev, 80,                     \
          "The standard deviation used by the parallel compact dead wood "  \
          "limiter (a number between 0-100)")                               \
          range(0, 100)                                                     \