Question

not sure if this question should be here or in serverfault, but it’s java-related so here it is:

I have two servers, with very similar technology:

• server1 is Oracle/Sun x86 with dual x5670 CPU (2.93 GHz) (4 cores each), 12GB RAM.
• server2 is Dell R610 with dual x5680 CPU (3.3 GHz) (6 cores each), 16GB RAM.

both are running Solaris x86, with exact same configuration.

both have turbo-boost enabled, and no hyper-threading.

server2 should therefore be SLIGHTLY faster than server1.

I’m running the following short test program on the two platforms.

import java.io.*;

public class TestProgram {

public static void main(String[] args) {
    new TestProgram ();
}

public TestProgram () {
    try {
        PrintWriter writer  = new PrintWriter(new FileOutputStream("perfs.txt", true), true);

        for (int i = 0; i < 10000; i++) {
            long t1 = System.nanoTime();
            System.out.println("0123456789qwertyuiop0123456789qwertyuiop0123456789qwertyuiop0123456789qwertyuiop");
            long t2 = System.nanoTime();

            writer.println((t2-t1));

            //try {
            //  Thread.sleep(1);
            //}
            //catch(Exception e) {
            //  System.out.println("thread sleep exception");
            //}
        }
    }
    catch(Exception e) {
        e.printStackTrace(System.out);
    }
}
}

I’m opening perfs.txt and averaging the results, I get:

• server1: average = 1664 , trim 10% = 1615
• server2: average = 1510 , trim 10% = 1429

which is a somewhat expected result (server2 perfs > server1 perfs).

now, I uncomment the “Thread.sleep(1)” part and test again, the results are now:

• server1: average = 27598 , trim 10% = 26583
• server2: average = 52320 , trim 10% = 39359

this time server2 perfs < server1 perfs

that doesn’t make any sense to me…

obviously I’m looking at a way to improve server2 perfs in the second case. there must be some kind of configuration that is different, and I don’t know which one.
OS are identical, java version are identical.

could it be linked to the number of cores ?
maybe it’s a BIOS setting ? although BIOS are different (AMI vs Dell), settings seem pretty similar.

I’ll update the Dell’s BIOS soon and retest, but I would appreciate any insight…

thanks

Answer 1

I actually updated the BIOS on the DELL R610 and ensured all BIOS CPU parameters are adjusted for best low-latency performances (no hyper-threading, etc…).
it solved it. The performances with & without the Thread.sleep make sense, and the overall performances of the R610 in both cases are much better than the Sun.
It appears the original BIOS did not make a correct or a full usage of the nehalem capabilities (while the Sun did).