In src/share/vm/prims/perf.cpp, Perf_CreateLong creates a perf counter of an incorrect type. As defined in perfData.hpp:
    enum Variability {
      V_Constant = 1,
      V_Monotonic = 2,
      V_Variable = 3,
      V_last = V_Variable
    };

Perf_CreateLong incorrectly creates a V_Variable perf long counter if variability == 2 and V_Monotonic if variability == 3.

The bug is in the switch statement:

  switch(variability) {
  case 1: /* V_Constant */
    pl = PerfDataManager::create_long_constant(NULL_NS, (char *)name_utf,
                                               (PerfData::Units)units, value,
                                               CHECK_NULL);
    break;

  case 2: /* V_Variable */
    pl = PerfDataManager::create_long_variable(NULL_NS, (char *)name_utf,
                                               (PerfData::Units)units, value,
                                               CHECK_NULL);
    break;

  case 3: /* V_Monotonic Counter */
    pl = PerfDataManager::create_long_counter(NULL_NS, (char *)name_utf,
                                              (PerfData::Units)units, value,
                                              CHECK_NULL);
    break;

  default: /* Illegal Argument */
    debug_only(warning("unexpected variability value: %d", variability));
    THROW_0(vmSymbols::java_lang_IllegalArgumentException());
    break;
  }