openjdk 1.8 分层编译功能验证¶
分层编译简介¶
1.JVM 分层编译参数测试¶
测试JVM使用不同控制参数影响编译器开启情况，未出现异常。 
Graal编译器 不支持，jdk10 引入，jdk1.8 没有 
jdk 1.8 c1,c2编译器监控确认没有生效。 
2.x86环境 情况对比¶
[root@njatwx-j08-03 javatest]# java -version
openjdk version "1.8.0_302"
OpenJDK Runtime Environment (build 1.8.0_302-b08)
OpenJDK 64-Bit Server VM (build 25.302-b08, mixed mode)
[root@njatwx-j08-03 javatest]# java -Xmixed -XX:+CITime -XX:+PrintCompilation -Xmx100m -Xms10m fannkuchredux 10
31 1 3 java.lang.Object::<init> (1 bytes)
31 2 3 java.lang.String::hashCode (55 bytes)
31 3 3 java.lang.String::indexOf (70 bytes)
32 4 3 java.lang.String::charAt (29 bytes)
32 5 3 java.lang.String::length (6 bytes)
32 6 n 0 java.lang.System::arraycopy (native) (static)
32 7 3 java.lang.Math::min (11 bytes)
32 8 3 java.lang.AbstractStringBuilder::ensureCapacityInternal (27 bytes)
32 9 1 java.lang.Object::<init> (1 bytes)
32 1 3 java.lang.Object::<init> (1 bytes) made not entrant
33 10 3 java.lang.String::equals (81 bytes)
35 11 1 java.lang.ref.Reference::get (5 bytes)
36 12 1 java.lang.ThreadLocal::access$400 (5 bytes)
36 13 3 java.util.Arrays::copyOfRange (63 bytes)
37 14 3 java.lang.System::getSecurityManager (4 bytes)
37 15 3 fannkuchredux::countFlips (118 bytes)
37 17 3 fannkuchredux::nextPermutation (112 bytes)
37 16 3 java.lang.Math::max (11 bytes)
39 18 3 java.lang.String::getChars (62 bytes)
59 20 4 fannkuchredux::nextPermutation (112 bytes)
60 19 4 fannkuchredux::countFlips (118 bytes)
63 17 3 fannkuchredux::nextPermutation (112 bytes) made not entrant
64 21 4 java.lang.Math::max (11 bytes)
64 16 3 java.lang.Math::max (11 bytes) made not entrant
75 15 3 fannkuchredux::countFlips (118 bytes) made not entrant
97 22 % 3 fannkuchredux::runTask @ 36 (115 bytes)
98 23 3 fannkuchredux::runTask (115 bytes)
170 24 % 4 fannkuchredux::runTask @ 36 (115 bytes)
175 22 % 3 fannkuchredux::runTask @ -2 (115 bytes) made not entrant
181 25 4 fannkuchredux::runTask (115 bytes)
187 23 3 fannkuchredux::runTask (115 bytes) made not entrant
196 26 3 fannkuchredux::firstPermutation (137 bytes)
73196
Pfannkuchen(10) = 38
Accumulated compiler times (for compiled methods only)
------------------------------------------------
Total compilation time : 0.035 s
Standard compilation : 0.029 s, Average : 0.001
On stack replacement : 0.006 s, Average : 0.003
Detailed C1 Timings
Setup time: 0.000 s ( 0.0%)
Build IR: 0.002 s (37.2%)
Optimize: 0.000 s ( 2.0%)
RCE: 0.000 s ( 1.1%)
Emit LIR: 0.002 s (37.8%)
LIR Gen: 0.000 s ( 9.4%)
Linear Scan: 0.001 s (27.8%)
LIR Schedule: 0.000 s ( 0.0%)
Code Emission: 0.001 s (14.9%)
Code Installation: 0.000 s (10.1%)
Instruction Nodes: 878 nodes
Total compiled methods : 25 methods
Standard compilation : 23 methods
On stack replacement : 2 methods
Total compiled bytecodes : 2138 bytes
Standard compilation : 1645 bytes
On stack replacement : 493 bytes
Average compilation speed: 61702 bytes/s
nmethod code size : 20704 bytes
nmethod total size : 37448 bytes
[root@njatwx-j08-03 javatest]# java -Xint -XX:+CITime -XX:+PrintCompilation -Xmx100m -Xms10m fannkuchredux 10
73196
Pfannkuchen(10) = 38
Accumulated compiler times (for compiled methods only)
------------------------------------------------
Total compilation time : 0.000 s
Standard compilation : 0.000 s, Average : -nan
On stack replacement : 0.000 s, Average : -nan
Total compiled methods : 0 methods
Standard compilation : 0 methods
On stack replacement : 0 methods
Total compiled bytecodes : 0 bytes
Standard compilation : 0 bytes
On stack replacement : 0 bytes
Average compilation speed: -2147483648 bytes/s
nmethod code size : 0 bytes
nmethod total size : 0 bytes