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6949307: G1: raise a vm error, do not core dump, if target pause time and target interval are inconsistent

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First, change the guarantee to raising a vm error. Second, set the interval dynamically, and based on the pause time target, if it is not set explicitly.

Reviewed-by: ysr, johnc
This commit is contained in:
Antonios Printezis 2010-05-07 13:14:41 -04:00
parent 428d02d5d7
commit a6d2266193
3 changed files with 58 additions and 9 deletions
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60
hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp
View file

@ -274,10 +274,64 @@ G1CollectorPolicy::G1CollectorPolicy() :
// </NEW PREDICTION>
double time_slice = (double) GCPauseIntervalMillis / 1000.0;
// Below, we might need to calculate the pause time target based on
// the pause interval. When we do so we are going to give G1 maximum
// flexibility and allow it to do pauses when it needs to. So, we'll
// arrange that the pause interval to be pause time target + 1 to
// ensure that a) the pause time target is maximized with respect to
// the pause interval and b) we maintain the invariant that pause
// time target < pause interval. If the user does not want this
// maximum flexibility, they will have to set the pause interval
// explicitly.
// First make sure that, if either parameter is set, its value is
// reasonable.
if (!FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
if (MaxGCPauseMillis < 1) {
vm_exit_during_initialization("MaxGCPauseMillis should be "
"greater than 0");
}
}
if (!FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
if (GCPauseIntervalMillis < 1) {
vm_exit_during_initialization("GCPauseIntervalMillis should be "
"greater than 0");
}
}
// Then, if the pause time target parameter was not set, set it to
// the default value.
if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
// The default pause time target in G1 is 200ms
FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
} else {
// We do not allow the pause interval to be set without the
// pause time target
vm_exit_during_initialization("GCPauseIntervalMillis cannot be set "
"without setting MaxGCPauseMillis");
}
}
// Then, if the interval parameter was not set, set it according to
// the pause time target (this will also deal with the case when the
// pause time target is the default value).
if (FLAG_IS_DEFAULT(GCPauseIntervalMillis)) {
FLAG_SET_DEFAULT(GCPauseIntervalMillis, MaxGCPauseMillis + 1);
}
// Finally, make sure that the two parameters are consistent.
if (MaxGCPauseMillis >= GCPauseIntervalMillis) {
char buffer[256];
jio_snprintf(buffer, 256,
"MaxGCPauseMillis (%u) should be less than "
"GCPauseIntervalMillis (%u)",
MaxGCPauseMillis, GCPauseIntervalMillis);
vm_exit_during_initialization(buffer);
}
double max_gc_time = (double) MaxGCPauseMillis / 1000.0;
guarantee(max_gc_time < time_slice,
"Max GC time should not be greater than the time slice");
double time_slice = (double) GCPauseIntervalMillis / 1000.0;
_mmu_tracker = new G1MMUTrackerQueue(time_slice, max_gc_time);
_sigma = (double) G1ConfidencePercent / 100.0;

5
hotspot/src/share/vm/runtime/arguments.cpp
View file

@ -1376,11 +1376,6 @@ void Arguments::set_g1_gc_flags() {
}
no_shared_spaces();
// Set the maximum pause time goal to be a reasonable default.
if (FLAG_IS_DEFAULT(MaxGCPauseMillis)) {
FLAG_SET_DEFAULT(MaxGCPauseMillis, 200);
}
if (FLAG_IS_DEFAULT(MarkStackSize)) {
FLAG_SET_DEFAULT(MarkStackSize, 128 * TASKQUEUE_SIZE);
}

2
hotspot/src/share/vm/runtime/globals.hpp
View file

@ -1975,7 +1975,7 @@ class CommandLineFlags {
"Adaptive size policy maximum GC pause time goal in msec, " \
"or (G1 Only) the max. GC time per MMU time slice") \
\
product(intx, GCPauseIntervalMillis, 500, \
product(uintx, GCPauseIntervalMillis, 0, \
"Time slice for MMU specification") \
\
product(uintx, MaxGCMinorPauseMillis, max_uintx, \