With 2 GB guest RAM VirtualBox is twenty times slower than with 700 MB RAM

[Jaan]

Steps to reproduce:

1. Download Ubuntu 10.04 32-bit Live CD ISO
2. Create a virtual machine with 2048 MB RAM and that ISO as CD-ROM and no hard drive
3. Run the virtual machine
4. Run "sudo apt-get install openjdk-6-jdk" on the guest to install Java
5. Copy the file SerTest.java (in attachment) to the guest's home directory
6. Run the following commands on the guest:

javac SerTest.java java SerTest 1000 100 0

I get output like this:

Creating 1000 objects... Done in 0.026094316000000003 seconds. Writing to test.ser... Done in 0.23731131500000002 seconds. Reading from test.ser... Done in 7.03051558 seconds. Checksum: -406759103

The 7 seconds for reading the file is an enormously long time.

If I change the virtual machine's RAM size to 700 MB and and repeat points 3-6 then I get the following, much better time:

Creating 1000 objects... Done in 0.017042552000000002 seconds. Writing to test.ser... Done in 0.11916187800000001 seconds. Reading from test.ser... Done in 0.36389537600000005 seconds. Checksum: -884318403

Increasing the object count in the test program increases run time proportionally, e. g. for "java SerTest 10000 100 0" the times are 70 seconds and 3 seconds for 2 GB RAM and 700 MB RAM, respectively.

The host is 64-bit Windows 7 with 4 GB RAM and Intel Core2 Duo E6400 processor.

[Jaan]

the benchmark program

[Jaan]

VBox.log with 2 GB guest RAM

[Jaan]

VBox.log with 700 MB guest RAM