From b5c192bb3dc57021996545b0bac822d73c75ec19 Mon Sep 17 00:00:00 2001
Date: Thu, 23 Apr 2020 16:12:34 +0800
Subject: [PATCH] add vm option BoxTypeCachedMax for Integer and Long cache
Summary: < JDK> : add vm option BoxTypeCachedMax for Integer and Long cache
LLT: NA
Bug url: NA
---
hotspot/src/share/vm/opto/c2_globals.hpp | 3 ++
hotspot/src/share/vm/runtime/arguments.cpp | 23 ++++++++++++
hotspot/src/share/vm/runtime/arguments.hpp | 3 ++
jdk/src/share/classes/java/lang/Long.java | 43 ++++++++++++++++++----
4 files changed, 65 insertions(+), 7 deletions(-)
diff --git a/hotspot/src/share/vm/opto/c2_globals.hpp b/hotspot/src/share/vm/opto/c2_globals.hpp
index 4b6a87508..3f2d286b2 100644
--- a/hotspot/src/share/vm/opto/c2_globals.hpp
+++ b/hotspot/src/share/vm/opto/c2_globals.hpp
@@ -470,6 +470,9 @@
product(intx, AutoBoxCacheMax, 128, \
"Sets max value cached by the java.lang.Integer autobox cache") \
\
+ product(intx, BoxTypeCachedMax, 128, \
+ "Sets max value cached by the java.lang.Long and Integer autobox cache") \
+ \
experimental(bool, AggressiveUnboxing, false, \
"Control optimizations for aggressive boxing elimination") \
\
diff --git a/hotspot/src/share/vm/runtime/arguments.cpp b/hotspot/src/share/vm/runtime/arguments.cpp
index 63b39c4ba..75ef29b9b 100644
--- a/hotspot/src/share/vm/runtime/arguments.cpp
+++ b/hotspot/src/share/vm/runtime/arguments.cpp
@@ -2194,6 +2194,24 @@ void Arguments::set_bytecode_flags() {
}
}
+// set Integer and Long box type cached MAX num flag : -XX:BoxTypeCachedMax=<size>
+void Arguments::set_boxtype_cached_max_flags() {
+ int size = 1024;
+ char buffer[size];
+ jio_snprintf(buffer, size, "java.lang.Long.LongCache.high=" INTX_FORMAT, BoxTypeCachedMax);
+ add_property(buffer);
+
+ if (AggressiveOpts || !FLAG_IS_DEFAULT(AutoBoxCacheMax)) {
+ if (FLAG_IS_DEFAULT(AutoBoxCacheMax)) {
+ FLAG_SET_DEFAULT(AutoBoxCacheMax, 20000);
+ }
+ jio_snprintf(buffer, size, "java.lang.Integer.IntegerCache.high=" INTX_FORMAT, AutoBoxCacheMax);
+ } else {
+ jio_snprintf(buffer, size, "java.lang.Integer.IntegerCache.high=" INTX_FORMAT, BoxTypeCachedMax);
+ }
+ add_property(buffer);
+}
+
// Aggressive optimization flags -XX:+AggressiveOpts
void Arguments::set_aggressive_opts_flags() {
#ifdef COMPILER2
@@ -2846,6 +2864,8 @@ bool Arguments::check_vm_args_consistency() {
// Check the minimum number of compiler threads
status &=verify_min_value(CICompilerCount, min_number_of_compiler_threads, "CICompilerCount");
+ status &= verify_min_value(BoxTypeCachedMax, 1, "BoxTypeCachedMax");
+
return status;
}
@@ -4336,6 +4356,9 @@ jint Arguments::apply_ergo() {
// Set bytecode rewriting flags
set_bytecode_flags();
+ // Set Integer and Long cached max
+ set_boxtype_cached_max_flags();
+
// Set flags if Aggressive optimization flags (-XX:+AggressiveOpts) enabled.
set_aggressive_opts_flags();
diff --git a/hotspot/src/share/vm/runtime/arguments.hpp b/hotspot/src/share/vm/runtime/arguments.hpp
index a5cd59ea6..6f7ff138f 100644
--- a/hotspot/src/share/vm/runtime/arguments.hpp
+++ b/hotspot/src/share/vm/runtime/arguments.hpp
@@ -386,6 +386,9 @@ class Arguments : AllStatic {
// System properties
static bool add_property(const char* prop);
+ // set Integer and Long box type cached MAX num
+ static void set_boxtype_cached_max_flags();
+
// Aggressive optimization flags.
static void set_aggressive_opts_flags();
diff --git a/jdk/src/share/classes/java/lang/Long.java b/jdk/src/share/classes/java/lang/Long.java
index 9e21cb853..d56f4c6be 100644
--- a/jdk/src/share/classes/java/lang/Long.java
+++ b/jdk/src/share/classes/java/lang/Long.java
@@ -804,13 +804,43 @@ public final class Long extends Number implements Comparable<Long> {
}
private static class LongCache {
+ static final int low;
+ static final int high;
+
private LongCache(){}
- static final Long cache[] = new Long[-(-128) + 127 + 1];
+ static final Long cache[];
static {
- for(int i = 0; i < cache.length; i++)
- cache[i] = new Long(i - 128);
+
+ String longCacheHighPropValue =
+ sun.misc.VM.getSavedProperty("java.lang.Long.LongCache.high");
+ if (longCacheHighPropValue != null) {
+ // high value may be configured by property
+ int h = 0;
+ try {
+ int i = Integer.parseInt(longCacheHighPropValue);
+ i = Math.max(i, 128);
+ // Maximum array size is Integer.MAX_VALUE
+ h = Math.min(i, Integer.MAX_VALUE/2 -1);
+ } catch( NumberFormatException nfe) {
+ // If the property cannot be parsed into an int, ignore it.
+ }
+ high = h;
+ low = -h+1;
+ cache = new Long[(high - low) + 1];
+ int j = low;
+ for(int k = 0; k < cache.length; k++)
+ cache[k] = new Long(j++);
+
+ } else {
+ low = -128;
+ high = 127;
+ cache = new Long[(high - low) + 1];
+ int j = low;
+ for(int k = 0; k < cache.length; k++)
+ cache[k] = new Long(j++);
+ }
}
}
@@ -833,10 +863,8 @@ public final class Long extends Number implements Comparable<Long> {
* @since 1.5
*/
public static Long valueOf(long l) {
- final int offset = 128;
- if (l >= -128 && l <= 127) { // will cache
- return LongCache.cache[(int)l + offset];
- }
+ if (l >= LongCache.low && l <= LongCache.high)
+ return LongCache.cache[(int) l + (-LongCache.low)];
return new Long(l);
}
@@ -1617,4 +1645,5 @@ public final class Long extends Number implements Comparable<Long> {
/** use serialVersionUID from JDK 1.0.2 for interoperability */
@Native private static final long serialVersionUID = 4290774380558885855L;
+
}
--
2.19.1