Java On Raspberry Pi Performance

My objective is to performance test basic JVM functions of different JVMs on the Raspberry Pi hardware to see which JVM is fastest overall. For this I have created a few different tests that exercise specific operations, such as floating-point math, file IO, etc. The results are not relevant compared to other hardware. The results metrics are really not important either other than as they compare to the same test on a different JVM.

VMs Tested

There's currently a few different JVMs available for Raspberry Pi. I tested these:

• Oracle ejre1.7.0_06

java version "1.7.0_06"
Java(TM) SE Embedded Runtime Environment (build 1.7.0_06-b24, headless)
Java HotSpot(TM) Embedded Client VM (build 23.2-b09, mixed mode)

• java-7-openjdk-armel with -zero

java version "1.7.0_03"
OpenJDK Runtime Environment (IcedTea7 2.1.3) (7u3-2.1.3-1)
OpenJDK Zero VM (build 22.0-b10, mixed mode)

• java-7-openjdk-armel with -cacao

java version "1.7.0_03"
IcedTea Runtime Environment (IcedTea7 2.1.3) (7u3-2.1.3-1)
CACAO (build 1.1.0pre2, compiled mode)

• java-7-openjdk-armel with -jamvm

java version "1.7.0_03"
OpenJDK Runtime Environment (IcedTea7 2.1.3) (7u3-2.1.3-1)
JamVM (build 1.6.0-devel, inline-threaded interpreter with stack-caching)

Startup Time

Tests HelloWorld is a basic print Hello World from a main method. This tests basic startup time. ResinVersion requests Resin version. It tests basic Resin startup time. ResinStatus requests status from a running Resin instance. The call fails as no instance was running, but that's not important. It tests realistic Resin startup and network connection. Results JamVM is clearly the fastest to startup but the margin is not huge. I believe this is due to the smaller size of this JVM. However the caveat is both Cacao and JamVM report warning when running both Resin tests. JamVM reports this: jmm_GetBoolAttribute: Unknown attribute 24 jmm_GetBoolAttribute: Unknown attribute 25 jmm_GetInputArgumentArray Cacao reports this: LOG: [0x400ec000] jmm_GetMemoryManagers: FIX ME! LOG: [0x400ec000] jmm_GetMemoryPools: FIX ME! LOG: [0x400ec000] jmm_GetBoolAttribute: Unknown attribute 24 LOG: [0x400ec000] jmm_GetBoolAttribute: Unknown attribute 25 LOG: [0x400ec000] jmm_GetInputArgumentArray: IMPLEMENT ME! These all look like warning associated with attempting to read MBean attributes from MBeans Resin is expecting to exist. Resin gleans a lot of info about OS and Memory Pools from JMX. I'll have to do more thorough Resin tests to see how adversely this effects Resin.

General Operations

Exceptions tests throwing and catching exception Hashing tests inserting into a map and retrieving from a map Reflection tests looking up a class by name and creating a new instance with Reflection Strings tests String creation and concatenation

Math

IO