8012371: Adjust Tiered compile threshold according to available space in code cache
Summary: Added command line parameter to define a threshold at which C1 compilation threshold for is increased.
Reviewed-by: kvn, iveresov
--- a/hotspot/src/share/vm/code/codeCache.cpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/code/codeCache.cpp Thu May 16 15:46:49 2013 +0200
@@ -622,6 +622,15 @@
return (address)_heap->high();
}
+/**
+ * Returns the reverse free ratio. E.g., if 25% (1/4) of the code cache
+ * is free, reverse_free_ratio() returns 4.
+ */
+double CodeCache::reverse_free_ratio() {
+ double unallocated_capacity = (double)(CodeCache::unallocated_capacity() - CodeCacheMinimumFreeSpace);
+ double max_capacity = (double)CodeCache::max_capacity();
+ return max_capacity / unallocated_capacity;
+}
void icache_init();
--- a/hotspot/src/share/vm/code/codeCache.hpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/code/codeCache.hpp Thu May 16 15:46:49 2013 +0200
@@ -163,6 +163,7 @@
static size_t max_capacity() { return _heap->max_capacity(); }
static size_t unallocated_capacity() { return _heap->unallocated_capacity(); }
static bool needs_flushing() { return unallocated_capacity() < CodeCacheFlushingMinimumFreeSpace; }
+ static double reverse_free_ratio();
static bool needs_cache_clean() { return _needs_cache_clean; }
static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; }
--- a/hotspot/src/share/vm/runtime/advancedThresholdPolicy.cpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/runtime/advancedThresholdPolicy.cpp Thu May 16 15:46:49 2013 +0200
@@ -68,7 +68,7 @@
}
#endif
-
+ set_increase_threshold_at_ratio();
set_start_time(os::javaTimeMillis());
}
@@ -205,6 +205,17 @@
double queue_size = CompileBroker::queue_size(level);
int comp_count = compiler_count(level);
double k = queue_size / (feedback_k * comp_count) + 1;
+
+ // Increase C1 compile threshold when the code cache is filled more
+ // than specified by IncreaseFirstTierCompileThresholdAt percentage.
+ // The main intention is to keep enough free space for C2 compiled code
+ // to achieve peak performance if the code cache is under stress.
+ if ((TieredStopAtLevel == CompLevel_full_optimization) && (level != CompLevel_full_optimization)) {
+ double current_reverse_free_ratio = CodeCache::reverse_free_ratio();
+ if (current_reverse_free_ratio > _increase_threshold_at_ratio) {
+ k *= exp(current_reverse_free_ratio - _increase_threshold_at_ratio);
+ }
+ }
return k;
}
--- a/hotspot/src/share/vm/runtime/advancedThresholdPolicy.hpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/runtime/advancedThresholdPolicy.hpp Thu May 16 15:46:49 2013 +0200
@@ -201,9 +201,12 @@
// Is method profiled enough?
bool is_method_profiled(Method* method);
+ double _increase_threshold_at_ratio;
+
protected:
void print_specific(EventType type, methodHandle mh, methodHandle imh, int bci, CompLevel level);
+ void set_increase_threshold_at_ratio() { _increase_threshold_at_ratio = 100 / (100 - (double)IncreaseFirstTierCompileThresholdAt); }
void set_start_time(jlong t) { _start_time = t; }
jlong start_time() const { return _start_time; }
--- a/hotspot/src/share/vm/runtime/arguments.cpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/runtime/arguments.cpp Thu May 16 15:46:49 2013 +0200
@@ -2629,6 +2629,16 @@
return JNI_EINVAL;
}
FLAG_SET_CMDLINE(uintx, ReservedCodeCacheSize, (uintx)long_ReservedCodeCacheSize);
+ //-XX:IncreaseFirstTierCompileThresholdAt=
+ } else if (match_option(option, "-XX:IncreaseFirstTierCompileThresholdAt=", &tail)) {
+ uintx uint_IncreaseFirstTierCompileThresholdAt = 0;
+ if (!parse_uintx(tail, &uint_IncreaseFirstTierCompileThresholdAt, 0) || uint_IncreaseFirstTierCompileThresholdAt > 99) {
+ jio_fprintf(defaultStream::error_stream(),
+ "Invalid value for IncreaseFirstTierCompileThresholdAt: %s. Should be between 0 and 99.\n",
+ option->optionString);
+ return JNI_EINVAL;
+ }
+ FLAG_SET_CMDLINE(uintx, IncreaseFirstTierCompileThresholdAt, (uintx)uint_IncreaseFirstTierCompileThresholdAt);
// -green
} else if (match_option(option, "-green", &tail)) {
jio_fprintf(defaultStream::error_stream(),
--- a/hotspot/src/share/vm/runtime/globals.hpp Fri May 17 09:10:04 2013 -0700
+++ b/hotspot/src/share/vm/runtime/globals.hpp Thu May 16 15:46:49 2013 +0200
@@ -3436,6 +3436,10 @@
"Start profiling in interpreter if the counters exceed tier 3" \
"thresholds by the specified percentage") \
\
+ product(uintx, IncreaseFirstTierCompileThresholdAt, 50, \
+ "Increase the compile threshold for C1 compilation if the code" \
+ "cache is filled by the specified percentage.") \
+ \
product(intx, TieredRateUpdateMinTime, 1, \
"Minimum rate sampling interval (in milliseconds)") \
\