Disclosure of tuning options for SPEC Java benchmark results:
Fujitsu Limited
March 15, 2006


JVM Command Line Options  ------------------------------------------------------

  -server:
      Use server (as opposed to client) JVM.

  -Xms<Size>:
      Sets the initial size of the heap. 

  -Xmx<Size>:
      Sets the maximum size of the heap.

  -Xmn<Size>: 	
      Set the size of the young generation (available beginning in J2SE 1.4.0). 

  -Xbatch:
      Disables background compilation.
        
  -Xss<Size>:	
      Sets the Java thread stack size.

  -XX:+UseParallelGC: 
      Use parallel garbage collection for the eden (young) generation 
      (available beginning in J2SE 1.4.0).

  -XX:+UseParallelGCThreads: The number of garbage collector threads 

  -XX:+UseParallelOldGC: 
      Use parallel garbage collection for the tenured (old) generation 
      (available beginning in J2SE 5.0_06).

  -XX:-XX:+UseBiasedLocking
      Enable biased locking.
      Enables a technique for improving the performance of uncontended 
      synchronization. An object is "biased" toward the thread which first 
      acquires its monitor via a monitorenter bytecode or synchronized method 
      invocation; subsequent monitor-related operations performed by that 
      thread are relatively much faster on multiprocessor machines. 
      Some applications with significant amounts of uncontended synchronization
      may attain significant speedups with this flag enabled; some applications
      with certain patterns of locking may see slowdowns, though attempts have 
      been made to minimize the negative impact. (available beginning with Java
      SE 5 update 6) 

  -XX;+AggressiveOpts
      Turns on point performance optimizations from the compiler that are 
      expected to be default in upcoming releases. This is a good flag to test 
      the JVM engineering team's latest performance tweaks that you'll see in 
      upcoming releases. (available beginning with Java SE 5 update 6) 

  -XX:+AggressiveHeap
      This option instructs the JVM to push memory use to the limit.

  -XX:+UseISM
      Use Solaris Intimate Shared Memory (ISM).

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/etc/system operating system tuning parameters --------------------------------
   
   autoup
      The frequency of file system sync operations. 

   tune_t_fsflushr 
      The number of seconds between fsflush invocations for checking 
      dirty memory. 

   shmsys:shminfo_shmmax
      Maximum size of system V shared memory segment that can be created.

   shmsys:shminfo_shmseg
      Limit on the number of shared memory segments that any one process 
      can create. 

   memscrub_period_sec
      Period of execution of the memory patrol daemon inunits of seconds. 
      This daemon periodically scans memory to confirm no ECC error.

   lgrp_mem_default_policy=2
      Allocate VM pages randomly for processes.

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Solaris User Command ---------------------------------------------------------

   psrset
      creation and management of processor sets.

      -e <processor_set_id>
            Executes a command (with optional  arguments)  in  the
            specified processor set.
        

   ppgsz
      set preferred page  size  for  stack,  heap,  and/or other anonymous 
      segments.
         
      -o  heap=size

           This option specifies  the  preferred page size for the heap of
           the target process(es). 

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