CPU2006 Flag Description
Cisco Systems Cisco UCS B420 M3 (Intel Xeon E5-4620, 2.2 GHz)

Copyright © 2006 Intel Corporation. All Rights Reserved.


Base Compiler Invocation

C benchmarks

C++ benchmarks


Peak Compiler Invocation

C benchmarks (except as noted below)

400.perlbench

445.gobmk

464.h264ref

C++ benchmarks (except as noted below)

473.astar


Base Portability Flags

400.perlbench

401.bzip2

403.gcc

429.mcf

445.gobmk

456.hmmer

458.sjeng

462.libquantum

464.h264ref

471.omnetpp

473.astar

483.xalancbmk


Peak Portability Flags

400.perlbench

401.bzip2

403.gcc

429.mcf

456.hmmer

458.sjeng

462.libquantum

473.astar

483.xalancbmk


Base Optimization Flags

C benchmarks

C++ benchmarks


Peak Optimization Flags

C benchmarks

400.perlbench

401.bzip2

403.gcc

429.mcf

445.gobmk

456.hmmer

458.sjeng

462.libquantum

464.h264ref

C++ benchmarks

471.omnetpp

473.astar

483.xalancbmk


Base Other Flags

C benchmarks

403.gcc


Peak Other Flags

C benchmarks

403.gcc


Implicitly Included Flags

This section contains descriptions of flags that were included implicitly by other flags, but which do not have a permanent home at SPEC.


Commands and Options Used to Submit Benchmark Runs

submit= MYMASK=`printf '0x%x' $((1<<$SPECCOPYNUM))`; /usr/bin/taskset $MYMASK $command
When running multiple copies of benchmarks, the SPEC config file feature submit is used to cause individual jobs to be bound to specific processors. This specific submit command, using taskset, is used for Linux64 systems without numactl.
Here is a brief guide to understanding the specific command which will be found in the config file:
submit= numactl --localalloc --physcpubind=$SPECCOPYNUM $command
When running multiple copies of benchmarks, the SPEC config file feature submit is used to cause individual jobs to be bound to specific processors. This specific submit command is used for Linux64 systems with support for numactl.
Here is a brief guide to understanding the specific command which will be found in the config file:

Shell, Environment, and Other Software Settings

numactl --interleave=all "runspec command"
Launching a process with numactl --interleave=all sets the memory interleave policy so that memory will be allocated using round robin on nodes. When memory cannot be allocated on the current interleave target fall back to other nodes.
KMP_STACKSIZE
Specify stack size to be allocated for each thread.
KMP_AFFINITY = granularity=fine,scatter
The value for the environment variable KMP_AFFINITY affects how the threads from an auto-parallelized program are scheduled across processors.
Specifying granularity=fine selects the finest granularity level, causes each OpenMP thread to be bound to a single thread context.
This ensures that there is only one thread per core on cores supporting HyperThreading Technology
Specifying scatter distributes the threads as evenly as possible across the entire system.
Hence a combination of these two options, will spread the threads evenly across sockets, with one thread per physical core.
OMP_NUM_THREADS
Sets the maximum number of threads to use for OpenMP* parallel regions if no other value is specified in the application. This environment variable applies to both -openmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows). Example syntax on a Linux system with 8 cores: export OMP_NUM_THREADS=8
Set stack size to unlimited
The command "ulimit -s unlimited" is used to set the stack size limit to unlimited.
Free the file system page cache
The command "echo 1> /proc/sys/vm/drop_caches" is used to free up the filesystem page cache.

Red Hat Specific features

Transparent Huge Pages
On RedHat EL 6 and later, Transparent Hugepages increase the memory page size from 4 kilobytes to 2 megabytes. Transparent Hugepages provide significant performance advantages on systems with highly contended resources and large memory workloads. If memory utilization is too high or memory is badly fragmented which prevents hugepages being allocated, the kernel will assign smaller 4k pages instead.
Hugepages are used by default unless the /sys/kernel/mm/redhat_transparent_hugepage/enabled field is changed from its RedHat EL6 default of 'always'.

Firmware / BIOS / Microcode Settings

Intel Turbo boost Technology:

Enabling this option allows the processor cores to automatically increase its frequency and increasing performance if it is running below power, temperature.

Intel Hyper Threading Technology:

Enabling this option allows to use processor resources more efficiently, enabling multiple threads to run on each core and increases processor throughput, improving overall performance on threaded software.

Enhanced Intel SpeedStep:

Enabling this option allows the system to dynamically adjust processor voltage and core frequency. This technology can result in decreased average power consumption and decreased average heat production.

Core Multi Processing:

This option Specifies the number of logical processor cores that can run on the server. This option sets he state of logical processor cores in a package. If you disable this setting, Hyper Threading is also disabled.

Virualization Technology:

If the processor uses Intel Virtualization Technology, which allows a platform to run multiple operating systems and applications in independent partitions. Users should disabled this option for performing application benchmarking.

Direct Cache Access:

Enabling this option allows processors to increase I/O performance by placing data from I/O devices directly into the processor cache. This setting helps to reduce cache misses.

Power Technology:

This BIOS option enables to configure the CPU power management settings such as Enhance Intel Speedstep technology, Intel Turbo Boost technology and Processor Power State C6. Settings in Custom will allows to change the CPU Power management settings. Settings in Energy Efficient will determine the best settings for the BIOS parameters. Settings in Disabled state does not perform any CPU power management and any settings for the BIOS paramaters.

Processor C1 Enhanced:

Enabling this option allows the processor to transition to its minimum frequency upon entering C1. This setting does not take effect until after you have rebooted the server. In disabled state, the CPU continues to run at its maximum frequency in C1 state. Users should disabled this option for performing application benchmarking.

Processor State C6:

Enabling this option allows the processor to send the C6 report to the Operating system. Users should disabled this option for performing application benchmarking.

Energy Performance:

This BIOS option allows you to determine whether system Performance or energy efficiency is more important on server. This can be one of the following: Balanced Energy, Balanced Performance, Energy Efficient and Performance. Note: Power Technology must be set to Custom to expose these BIOS option.

CPU Performance:

This BIOS option allows the enabling/disabling of a processor mechanism in 3 modes Enterprise, High-Throughput and HPC. Setting this BIOS option in Enterprise and High-throughput mode, will enable all the prefetchers and disables Data Reuse technology. Setting this BIOS option in HPC mode, will enable all the prefetchers and enables Data Reuse technology.

Low Voltage DDR Mode and DRAM Clock Throttling:

This BIOS option allows the enabling/disabling of a memory operations. Setting this BIOS option in Power-saving-mode, will prioritizes low voltage memory operations over high frequency memory operations. This mode may lower memory frequency in order to keep the voltage low. Setting this BIOS option in Performance-mode, will prioritizes high frequency operations over low voltage operations.

High Bandwidth:

Enabling this option allows the chipset to defer memory transactions and process them out of order for optimal performance.

ulimit -s <n>

Sets the stack size to n kbytes, or unlimited to allow the stack size to grow without limit.

numactl --interleave=all "runspec command"

Launching a process with numactl --interleave=all sets the memory interleave policy so that memory will be allocated using round robin on nodes. When memory cannot be allocated on the current interleave target fall back to other nodes.

Free the file system page cache

The command "echo 1> /proc/sys/vm/drop_caches" is used to free up the filesystem page cache.

Using numactl to bind processes and memory to cores

For multi-copy runs or single copy runs on systems with multiple sockets, it is advantageous to bind a process to a particular core. Otherwise, the OS may arbitrarily move your process from one core to another. This can effect performance. To help, SPEC allows the use of a "submit" command where users can specify a utility to use to bind processes. We have found the utility 'numactl' to be the best choice.

numactl runs processes with a specific NUMA scheduling or memory placement policy. The policy is set for a command and inherited by all of its children. The numactl flag "--physcpubind" specifies which core(s) to bind the process. "-l" instructs numactl to keep a process memory on the local node while "-m" specifies which node(s) to place a process memory. For full details on using numactl, please refer to your Linux documentation, 'man numactl'

Linux Huge Page settings

In order to take advantage of large pages, your system must be configured to use large pages. To configure your system for huge pages perform the following steps:

Create a mount point for the huge pages: "mkdir /mnt/hugepages" The huge page file system needs to be mounted when the systems reboots. Add the following to a system boot configuration file before any services are started: "mount -t hugetlbfs nodev /mnt/hugepages" Set vm/nr_hugepages=N in your /etc/sysctl.conf file where N is the maximum number of pages the system may allocate. Reboot to have the changes take effect.(Not necessary on some operating systems like RedHat Enterprise Linux 5.5.

Note that further information about huge pages may be found in your Linux documentation file: /usr/src/linux/Documentation/vm/hugetlbpage.txt

Transparent Huge Pages

On RedHat EL 6 and later, Transparent Hugepages increase the memory page size from 4 kilobytes to 2 megabytes. Transparent Hugepages provide significant performance advantages on systems with highly contended resources and large memory workloads. If memory utilization is too high or memory is badly fragmented which prevents hugepages being allocated, the kernel will assign smaller 4k pages instead. Hugepages are used by default if /sys/kernel/mm/redhat_transparent_hugepage/enabled is set to always

HUGETLB_MORECORE

Set this environment variable to "yes" to enable applications to use large pages.

LD_PRELOAD=/usr/lib64/libhugetlbfs.so

Setting this environment variable is necessary to enable applications to use large pages.

KMP_STACKSIZE

Specify stack size to be allocated for each thread.

KMP_AFFINITY

KMP_AFFINITY = < physical | logical >, starting-core-id specifies the static mapping of user threads to physical cores. For example, if you have a system configured with 8 cores, OMP_NUM_THREADS=8 and KMP_AFFINITY=physical,0 then thread 0 will mapped to core 0, thread 1 will be mapped to core 1, and so on in a round-robin fashion. KMP_AFFINITY = granularity=fine,scatter The value for the environment variable KMP_AFFINITY affects how the threads from an auto-parallelized program are scheduled across processors. Specifying granularity=fine selects the finest granularity level, causes each OpenMP thread to be bound to a single thread context. This ensures that there is only one thread per core on cores supporting HyperThreading Technology Specifying scatter distributes the threads as evenly as possible across the entire system. Hence a combination of these two options, will spread the threads evenly across sockets, with one thread per physical core.

OMP_NUM_THREADS

Sets the maximum number of threads to use for OpenMP* parallel regions if no other value is specified in the application. This environment variable applies to both -openmp and -parallel (Linux and Mac OS X) or /Qopenmp and /Qparallel (Windows). Example syntax on a Linux system with 8 cores: export OMP_NUM_THREADS=8

submit= MYMASK=`printf '0x%x' \$((1<<\$SPECCOPYNUM))`; /usr/bin/taskset \$MYMASK $command

When running multiple copies of benchmarks, the SPEC config file feature submit is sometimes used to cause individual jobs to be bound to specific processors. This specific submit command is used for Linux. The description of the elements of the command are: /usr/bin/taskset [options] [mask] [pid | command [arg] ... ]: taskset is used to set or retreive the CPU affinity of a running process given its PID or to launch a new COMMAND with a given CPU affinity. The CPU affinity is represented as a bitmask, with the lowest order bit corresponding to the first logical CPU and highest order bit corresponding to the last logical CPU. When the taskset returns, it is guaranteed that the given program has been scheduled to a legal CPU. The default behaviour of taskset is to run a new command with a given affinity mask: taskset [mask] [command] [arguments] $MYMASK: The bitmask (in hexadecimal) corresponding to a specific SPECCOPYNUM. For example, $MYMASK value for the first copy of a rate run will be 0x00000001, for the second copy of the rate will be 0x00000002 etc. Thus, the first copy of the rate run will have a CPU affinity of CPU0, the second copy will have the affinity CPU1 etc. $command: Program to be started, in this case, the benchmark instance to be started.

mysubmit.pl

This perl script is used to ensure that for a system with N cores the first N/2 benchmark copies are bound to a core that does not share its L2 cache with any of the other copies. The script does this by retrieving and using CPU data from /proc/cpuinfo. Note this script will only work for 6-core CPUs.

  • Source
    ******************************************************************************************************
    #!/usr/bin/perl

    use strict;
    use Cwd;

    # The order in which we want copies to be bound to cores
    # Copies: 0, 1, 2, 3
    # Cores: 0, 1, 3, 6

    my $rundir = getcwd;

    my $copynum = shift @ARGV;

    my $i;
    my $j;
    my $tag;
    my $num;
    my $core;

    my @proc;
    my @cores;

    open(INPUT, "/proc/cpuinfo") or
    die "can't open /proc/cpuinfo\n";

    #open(OUTPUT, "STDOUT");

    # proc[i][0] = logical processor ID
    # proc[i][1] = physical processor ID
    # proc[i][2] = core ID

    $i = 0;

    while(<INPUT>)
    {
    chop;

    ($tag, $num) = split(/\s+:\s+/, $_);


    if ($tag eq "processor") {
    $proc[$i][0] = $num;
    }

    if ($tag eq "physical id") {
    $proc[$i][1] = $num;
    }

    if ($tag eq "core id") {
    $proc[$i][2] = $num;
    $i++;
    }
    }

    $i = 0;
    $j = 0;

    for $core (0, 4, 2, 1, 5, 3) {
    while ($i < 24) {
    if ($proc[$i][2] == $core) {
    $cores[$j] = $proc[$i][0];
    $j++;
    }
    $i++;
    }
    $i=0;
    }

    open RUNCOMMAND, "> runcommand" or die "failed to create run file";
    print RUNCOMMAND "cd $rundir\n";
    print RUNCOMMAND "@ARGV\n";
    close RUNCOMMAND;
    system 'taskset', '-c', $cores[$copynum], 'sh', "$rundir/runcommand";

Flag description origin markings:

[user] Indicates that the flag description came from the user flags file.
[suite] Indicates that the flag description came from the suite-wide flags file.
[benchmark] Indicates that the flag description came from a per-benchmark flags file.

The flags files that were used to format this result can be browsed at
http://www.spec.org/cpu2006/flags/Intel-ic13-official-linux64.html,
http://www.spec.org/cpu2006/flags/Cisco-Platform-Settings-V1.2.20130607.html.

You can also download the XML flags sources by saving the following links:
http://www.spec.org/cpu2006/flags/Intel-ic13-official-linux64.xml,
http://www.spec.org/cpu2006/flags/Cisco-Platform-Settings-V1.2.20130607.xml.


For questions about the meanings of these flags, please contact the tester.
For other inquiries, please contact webmaster@spec.org
Copyright 2006-2014 Standard Performance Evaluation Corporation
Tested with SPEC CPU2006 v1.2.
Report generated on Thu Jul 24 15:28:45 2014 by SPEC CPU2006 flags formatter v6906.