- “AST interpreter”
- Framework for writing new languages etc
- Example languages implemented so far
- Ruby, JavaScript, Python, Lua, R and few more experimental languages
- LLVM bit code interpreter (Compile C/C++ into LLVM bit code, then interpret that one!)
- Interpreting C (Interpret C code directly, without using LLVM etc)
- Alternate compiler (to standard JVM’s “server”, “client” compilers)
- Written in Java
- Uses JVMCI interface (so that the compiler doesn’t have to be in C++ but can still be part of JVM)
- Can do JIT or AOT compilation
- Has advanced compilation methods: Improved speculative optimization and deoptimizations, partial escape analysis etc
- A JVM that has Graal compiler support
- Only compiler part of JVM is replaced, rest of the JVM is used almost as is (GC, Interpreter etc)
- A new JVM written from ground up (in JVM!)
- It can compile to native code using Graal/Truffle’s AOT feature: so warmup time and memory usage issues are addressed to an extent.
- Limitations: https://github.com/oracle/graal/blob/master/substratevm/LIMITATIONS.md
- We can use Graal compiler (either use GraalVM package, or use in Java9,
“-XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI
-XX:+UseJVMCICompiler”), as an alternative to “-server” or
“-client”. This should be a drop in replacement and should bring
whatever benefits Graal compiler itself offers.
Note that we will still have warmup issues (probably bit more since Graal compiler is written in Java, so the compiler itself will take time to warmup!), but should improve “peak performance”, probably this is what we are interested in server machines.
- For smaller/standalone java programs, we might want to try out SubstrateVM (due to improved startup time)
- For our own DSL, we can use Truffle (so we can magically get JIT, AOT etc)
Time for (almost useless) microbenchmark
All time in ms
| C | Go | Java8 | Java9 | GraalVM (java8 based) | Java9 + Graal via JVMCI | SubstrateVM + AOT | C + LLVM bitcode interpreter |
|---|---|---|---|---|---|---|---|
| 0.34 | 0.86 | 73.8 | 174.2 | 97.3 | 157.6 | 2.1 | 106.2 |
Actual runs:
$ cat hello.c
#include <stdio.h>
int main() {
printf("Hello from C\n");
return 0;
}
$ cat HelloWorld.java
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello from Java");
}
}
$ cat hello.go
package main
import "fmt"
func main() {
fmt.Println("Hello from Go")
}
#########################################################
# C Hello world
$ gcc --version
gcc (GCC) 7.3.1 20180312
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ gcc -o hello hello.c # adding -static option would improve perf
$ perf stat -e cpu-clock -r100 ./hello >/dev/null
Performance counter stats for './hello' (100 runs):
0.347559 cpu-clock:u (msec) # 0.597 CPUs utilized ( +- 1.08% )
0.000581927 seconds time elapsed ( +- 1.06% )
#########################################################
# Go hello world
$ go version
go version go1.10.1 linux/amd64
$ go build hello.go
$ perf stat -e cpu-clock -r100 ./hello >/dev/null
Performance counter stats for './hello' (100 runs):
0.862860 cpu-clock:u (msec) # 0.884 CPUs utilized ( +- 1.14% )
0.000976005 seconds time elapsed ( +- 1.55% )
#########################################################
# Java hello world(s)
#########################################################
# Java8
$ export PATH=/usr/lib/jvm/java-8-openjdk/bin:$PATH
$ java -version
openjdk version "1.8.0_162"
OpenJDK Runtime Environment (build 1.8.0_162-b12)
OpenJDK 64-Bit Server VM (build 25.162-b12, mixed mode)
$ javac HelloWorld.java
$ perf stat -e cpu-clock -r50 java HelloWorld >/dev/null
Performance counter stats for 'java HelloWorld' (50 runs):
73.870517 cpu-clock:u (msec) # 1.111 CPUs utilized ( +- 0.80% )
0.066500354 seconds time elapsed ( +- 0.97% )
#########################################################
# Java9
$ export PATH=/usr/lib/jvm/java-9-openjdk/bin:$PATH
$ java -version
openjdk version "9.0.4"
OpenJDK Runtime Environment (build 9.0.4+11)
OpenJDK 64-Bit Server VM (build 9.0.4+11, mixed mode)
$ javac HelloWorld.java
$ perf stat -e cpu-clock -r100 java HelloWorld >/dev/null
Performance counter stats for 'java HelloWorld' (100 runs):
174.249613 cpu-clock:u (msec) # 1.390 CPUs utilized ( +- 0.46% )
0.125355882 seconds time elapsed ( +- 0.61% )
#########################################################
# GraalVM (Java 8 based)
$ export PATH=~/bin/graalvm-1.0.0-rc1/bin/:$PATH
$ java -version
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
GraalVM 1.0.0-rc1 (build 25.71-b01-internal-jvmci-0.42, mixed mode)
$ javac HelloWorld.java
$ perf stat -e cpu-clock -r100 java HelloWorld >/dev/null
Performance counter stats for 'java HelloWorld' (100 runs):
97.356289 cpu-clock:u (msec) # 1.147 CPUs utilized ( +- 0.59% )
0.084870116 seconds time elapsed ( +- 0.73% )
#########################################################
# Java9 + JVMCI + Graal compiler
$ export PATH=/usr/lib/jvm/java-9-openjdk/bin:$PATH
$ java -version
openjdk version "9.0.4"
OpenJDK Runtime Environment (build 9.0.4+11)
OpenJDK 64-Bit Server VM (build 9.0.4+11, mixed mode)
$ javac HelloWorld.java
$ perf stat -e cpu-clock -r100 java -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseJVMCICompiler HelloWorld >/dev/null
Performance counter stats for 'java -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCI -XX:+UseJVMCICompiler HelloWorld' (100 runs):
157.698255 cpu-clock:u (msec) # 1.260 CPUs utilized ( +- 0.47% )
0.125177189 seconds time elapsed ( +- 0.60% )
#########################################################
# SubstrateVM (AOT, compiled to native)
$ export PATH=~/bin/graalvm-1.0.0-rc1/bin/:$PATH
$ java -version
java version "1.8.0_161"
Java(TM) SE Runtime Environment (build 1.8.0_161-b12)
GraalVM 1.0.0-rc1 (build 25.71-b01-internal-jvmci-0.42, mixed mode)
$ javac HelloWorld.java
$ native-image HelloWorld
Build on Server(pid: 17224, port: 26681)
classlist: 411.03 ms
(cap): 1,131.85 ms
setup: 1,599.90 ms
(typeflow): 2,843.89 ms
(objects): 1,537.76 ms
(features): 31.64 ms
analysis: 4,526.03 ms
universe: 223.39 ms
(parse): 518.79 ms
(inline): 710.92 ms
(compile): 3,760.82 ms
compile: 5,466.79 ms
image: 776.56 ms
write: 231.92 ms
[total]: 13,280.51 ms
$ file ./helloworld
./helloworld: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=e4fa9799f7d2ff4d5715dbfe9b0d07f5e619b675, stripped
$ ldd ./helloworld
linux-vdso.so.1 (0x00007ffee5fd1000)
libdl.so.2 => /usr/lib/libdl.so.2 (0x00007f534bcac000)
libpthread.so.0 => /usr/lib/libpthread.so.0 (0x00007f534ba8e000)
libz.so.1 => /usr/lib/libz.so.1 (0x00007f534b877000)
librt.so.1 => /usr/lib/librt.so.1 (0x00007f534b66f000)
libcrypt.so.1 => /usr/lib/libcrypt.so.1 (0x00007f534b437000)
libc.so.6 => /usr/lib/libc.so.6 (0x00007f534b080000)
/lib64/ld-linux-x86-64.so.2 => /usr/lib64/ld-linux-x86-64.so.2 (0x00007f534c744000)
$ ls -lh helloworld
-rwxr-xr-x 1 suresh users 6.6M Apr 19 15:05 helloworld
$ perf stat -e cpu-clock -r100 ./helloworld >/dev/null
Performance counter stats for './helloworld' (100 runs):
2.127336 cpu-clock:u (msec) # 0.894 CPUs utilized ( +- 0.94% )
0.002378289 seconds time elapsed ( +- 0.91% )
#########################################################
# LLVM bit core interpreter
$ clang -c -O1 -emit-llvm hello.c
$ perf stat -e cpu-clock -r100 lli hello.bc >/dev/null
Performance counter stats for 'lli hello.bc' (100 runs):
106.270393 cpu-clock:u (msec) # 1.320 CPUs utilized ( +- 0.99% )
0.080493463 seconds time elapsed ( +- 0.77% )