jvm-hotspot

问题 (note: proper answer must go beyond reproduction). After millions of invocations, quicksort1 is definitely faster than quicksort2, which have identical code aside from this 1 extra arg. The code is at the end of the post. Spoiler: I also found the jit code is fatter by 224 bytes even if it should be actually simpler (like the byte code size tells; see very last update below). Even after trying to factor out this effect with some microbenchmark harness (JMH), the performance difference is

问题 (note: proper answer must go beyond reproduction). After millions of invocations, quicksort1 is definitely faster than quicksort2, which have identical code aside from this 1 extra arg. The code is at the end of the post. Spoiler: I also found the jit code is fatter by 224 bytes even if it should be actually simpler (like the byte code size tells; see very last update below). Even after trying to factor out this effect with some microbenchmark harness (JMH), the performance difference is

问题 (note: proper answer must go beyond reproduction). After millions of invocations, quicksort1 is definitely faster than quicksort2, which have identical code aside from this 1 extra arg. The code is at the end of the post. Spoiler: I also found the jit code is fatter by 224 bytes even if it should be actually simpler (like the byte code size tells; see very last update below). Even after trying to factor out this effect with some microbenchmark harness (JMH), the performance difference is

问题 The question is can we cache jclass and jmethodID across different JNI methods invocation? I faced some strange behavior when trying to create an object of some specific class with cached jclass and jmethodID from another JNI method invocation. Here is a simple example: public class Main { static { System.loadLibrary("test-crash"); } public static void main(String args[]) throws InterruptedException { Thread.sleep(20000); doAnotherAction(doSomeAction()); } private static native long

问题 I am trying to dive deep into volatile keyword in Java and setup 2 testing environments. I believe both of them are with x86_64 and use hotspot. Java version: 1.8.0_232 CPU: AMD Ryzen 7 8Core Java version: 1.8.0_231 CPU: Intel I7 Code is here: import java.lang.reflect.Field; import sun.misc.Unsafe; public class Test { private boolean flag = true; //left non-volatile intentionally private volatile int dummyVolatile = 1; public static void main(String[] args) throws Exception { Test t = new

问题 I am trying to dive deep into volatile keyword in Java and setup 2 testing environments. I believe both of them are with x86_64 and use hotspot. Java version: 1.8.0_232 CPU: AMD Ryzen 7 8Core Java version: 1.8.0_231 CPU: Intel I7 Code is here: import java.lang.reflect.Field; import sun.misc.Unsafe; public class Test { private boolean flag = true; //left non-volatile intentionally private volatile int dummyVolatile = 1; public static void main(String[] args) throws Exception { Test t = new

问题 While playing with some jcstress code, I noticed two parameters that are very new to me: StressLCM and StressGCM . The very first thing to do for me was searching for these in the source code itself and while I have found some things, it is still unclear what they actually do. I was really hoping to see some comments in the source code that would shed some light, but no luck. I also found the bug description where these have been added, but the explanation made no sense for me: Randomize

来源： https://stackoverflow.com/questions/63077785/will-jvm-evaluate-a-obvious-return-value-on-each-execution

来源： https://stackoverflow.com/questions/62304946/is-it-possible-to-enable-caching-of-native-code

来源： https://stackoverflow.com/questions/62304946/is-it-possible-to-enable-caching-of-native-code