IBM Power Linux Flags file

Commands and Options Used to Submit Benchmark Runs

submit = numactl -l -C $BIND $command

• Each process was bound to a cpu using submit= with the numactl command

   
  submit = numactl --membind=\$SPECCOPYNUM --physcpubind=\$SPECCOPYNUM $command
  submit = numactl -l -C $BIND $command
  

• numactl : Control NUMA policy for processes or shared memory

   
        -l
         Allocates memory from the local node of the cpu.
  
       --membind=nodes
         Only  allocate  memory  from  nodes.   Allocation will fail when
         there is not enough memory available on these nodes.
  
       -C
      --physcpubind=cpus
         Only execute process on cpus.  This accepts physical cpu numbers
         as shown in the processor fields of /proc/cpuinfo.
  

Shell, Environment, and Other Software Settings

• Environment variables that can be set before the run:

  XLFRTEOPTS=intrinthrds=1 : Causes the Fortran runtime to only use a single thread.
  

• To reserve 200 huge pages out of the physical memory pool, issue the following command,

  echo 200 > /proc/sys/vm/nr_hugepages
  

  or

  echo 200 > /proc/sys/vm/nr_overcommit_hugepages
  

  to allocate from the dynamic hugepage pool. This can be done in both Red Hat and Suse Enterprise, since both distributions implements Transparent Huge Pages (THP). THP is an abstraction layer that automates most aspects of creating, managing and using huge pages, and can currently only map anonymous memory regions such as heap and stack space.

  You can also use the environment variables below to manage huge pages behavior:
  
  HUGETLB_VERBOSE=0 : Turn off any debugging message from libhugetlbfs
  HUGETLB_MORECORE=yes:  Instructs libhugetlbfs to override libc's normal morecore() function with a hugepage version and use it for malloc(). 
  HUGETLB_MORECORE_HEAPBASE=0x50000000: Specifies that the hugepage heap address to start at 0x50000000. 
  HUGETLB_ELFMAP=R ; Instructs libhugetlbfs to place text segment in hugepages.
  HUGETLB_ELFMAP=W ; Instructs libhugetlbfs to place data and BSS segments in hugepages.
  HUGETLB_ELFMAP=RW ; Instructs libhugetlbfs to place all segments in hugepages.
  HUGETLB_ELFMAP=no ; Instructs libhugetlbfs not to place any segment in hugepages.
  

Operating System Tuning Parameters

• ulimit -s 1048576
  Sets the maximum stack size to "1048576 KB".

Firmware / BIOS / Microcode Settings

• Idle Power Saving

       Enables idle mode power reduction methods, when in Nominal, SPS, DPS.
       Drop in frequency, voltage.
	   Enable core-folding to exploit P7+ deep-sleep mode.
	   
	   Goal is to meet idle power criteria for EnergyStar v1 and v2 tests.
            1. Enter “idle” 5-15 minutes after full load test.
            2. Measure system power for 5 minutes.
            3. Report system power as average measured in step 2.
            4. If the value reported in step 3 is below a “computed threshold” the system qualifies for EnergyStar label.
			
       To Enable or disable the Idle Power Saving log into Advanced System Management web interface and go to 
       System Configurator -> Power Management and click into Idle Power Saver. Select enabled or disabled in the combo
       box and click in Save settings.