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<?xml version="1.0"?>
<!DOCTYPE flagsdescription SYSTEM "http://www.spec.org/dtd/cpuflags2.dtd">
<flagsdescription>
<!-- filename to begin with "HP-Intel-Linux-Settings" -->
<filename>HP-Intel-Linux-Settings-flags</filename>
<title>SPEC CPU2006 Software OS and BIOS tuning Descriptions HP ProLiant Intel-based systems
applications</title>
<!--
*********************************************************************************************************************
Explanations of platform info, such as BIOS settings
*********************************************************************************************************************
-->
<submit_command>
<![CDATA[
<p><b> submit= MYMASK=`printf '0x%x' \$((1<<\$SPECCOPYNUM))`; /usr/bin/taskset \$MYMASK $command </b></p>
<p>
When running multiple copies of benchmarks, the SPEC config file feature
<b>submit</b> is sometimes used to cause individual jobs to be bound to
specific processors. This specific submit command is used for Linux.
The description of the elements of the command are:</p>
<ul>
<li> <b>/usr/bin/taskset [options] [mask] [pid | command [arg] ... ]</b>: <br />
taskset is used to set or retreive the CPU affinity of a running
process given its PID or to launch a new COMMAND with a given CPU
affinity. The CPU affinity is represented as a bitmask, with the
lowest order bit corresponding to the first logical CPU and highest
order bit corresponding to the last logical CPU. When the taskset
returns, it is guaranteed that the given program has been scheduled
to a legal CPU. <br /><br />
The default behaviour of taskset is to run a new command with a
given affinity mask: <br /><br />
taskset [mask] [command] [arguments] </li>
<li> <b>$MYMASK</b>: The bitmask (in hexadecimal) corresponding to a specific
SPECCOPYNUM. For example, $MYMASK value for the first copy of a
rate run will be 0x00000001, for the second copy of the rate will
be 0x00000002 etc. Thus, the first copy of the rate run will have a
CPU affinity of CPU0, the second copy will have the affinity CPU1
etc.</li>
<li> <b>$command</b>: Program to be started, in this case, the benchmark instance
to be started. </li>
</ul>
<p><b>Using numactl to bind processes and memory to cores</b></p>
<p>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.</p>
<p>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'</p>
<p><b> mysubmit.pl</b></p>
<p>
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.</p>
<ul>
<li><b>Source</b><br />
******************************************************************************************************<br />
#!/usr/bin/perl<br />
<br />
use strict;<br />
use Cwd;<br />
<br />
# The order in which we want copies to be bound to cores<br />
# Copies: 0, 1, 2, 3<br />
# Cores: 0, 1, 3, 6<br />
<br />
my $rundir = getcwd;<br />
<br />
my $copynum = shift @ARGV;<br />
<br />
my $i;<br />
my $j;<br />
my $tag;<br />
my $num;<br />
my $core;<br />
<br />
my @proc;<br />
my @cores;<br />
<br />
open(INPUT, "/proc/cpuinfo") or<br />
die "can't open /proc/cpuinfo\n";<br />
<br />
#open(OUTPUT, "STDOUT");<br />
<br />
# proc[i][0] = logical processor ID<br />
# proc[i][1] = physical processor ID<br />
# proc[i][2] = core ID<br />
<br />
$i = 0;<br />
<br />
while(<INPUT>)<br />
{<br />
chop;<br />
<br />
($tag, $num) = split(/\s+:\s+/, $_);<br />
<br />
<br />
if ($tag eq "processor") {<br />
$proc[$i][0] = $num;<br />
}<br />
<br />
if ($tag eq "physical id") {<br />
$proc[$i][1] = $num;<br />
}<br />
<br />
if ($tag eq "core id") {<br />
$proc[$i][2] = $num;<br />
$i++;<br />
}<br />
}<br />
<br />
$i = 0;<br />
$j = 0;<br />
<br />
for $core (0, 4, 2, 1, 5, 3) {<br />
while ($i < 24) {<br />
if ($proc[$i][2] == $core) {<br />
$cores[$j] = $proc[$i][0];<br />
$j++;<br />
}<br />
$i++;<br />
}<br />
$i=0;<br />
}<br />
<br />
open RUNCOMMAND, "> runcommand" or die "failed to create run file";<br />
print RUNCOMMAND "cd $rundir\n";<br />
print RUNCOMMAND "@ARGV\n";<br />
close RUNCOMMAND;<br />
system 'taskset', '-c', $cores[$copynum], 'sh', "$rundir/runcommand";<br />
</li></ul>
]]>
</submit_command>
<sw_environment>
<![CDATA[
<p><b> ulimit -s [n | unlimited] (Linux) </b></p>
<p>
Sets the stack size to <b>n</b> kbytes, or <b>unlimited</b> to allow the stack size
to grow without limit. </p>
<p><b> KMP_STACKSIZE=integer[B|K|M|G|T] (Linux) </b></p>
<p>
Sets the number of bytes to allocate for each parallel thread to use as its
private stack. Use the optional suffix B, K, M, G, or T, to specify bytes,
kilobytes, megabytes, gigabytes, or terabytes. The default setting is 2M on
IA32 and 4M on IA64. </p>
<p><b> KMP_AFFINITY=physical,n (Linux) </b></p>
<p>
Assigns threads to consecutive physical processors (for example, cores),
beginning at processor n. Specifies the static mapping of user threads to
physical cores, beginning at processor n. For example, if a system is configured
with 8 cores, and OMP_NUM_THREADS=8 and KMP_AFFINITY=physical,2 are set, then
thread 0 will mapped to core 2, thread 1 will be mapped to core 3, and so on in
a round-robin fashion. </p>
<p><b> KMP_AFFINITY=granularity=fine,scatter </b></p>
<p>
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. </p>
<p><b> OMP_NUM_THREADS=n </b></p>
<p>
This Environment Variable sets the maximum number of threads to use for OpenMP*
parallel regions to <b>n</b> if no other value is specified in the application. This
environment variable applies to both -openmp and -parallel (Linux)
or /Qopenmp and /Qparallel (Windows). Example syntax on a Linux system with 8
cores:<br />
export OMP_NUM_THREADS=8<br />
Default is the number of cores visible to the OS.
</p>
<p><b> vm.max_map_count-n (Linux) </b></p>
<p>
The maximum number of memory map areas a process may have. Memory map areas
are used as a side-effect of calling malloc, directly by mmap and mprotect,
and also when loading shared libraries. </p>
]]>
</sw_environment>
<os_tuning>
<![CDATA[
]]>
</os_tuning>
<firmware>
<![CDATA[
<p><b>Platform settings</b></p>
<p>One or more of the following settings may have been set. If so, the "Platform Notes" section of the
report will say so; and you can read below to find out more about what these settings mean.</p>
<p><b>Power Regulator for ProLiant support (Default=HP Dynamic Power Savings Mode)</b></p>
<p>Values for this BIOS setting can be:</p>
<ul>
<li><b>HP Dynamic Power Savings Mode</b>: Automatically varies processor
speed and power usage based on processor utilization. Allows
reducing overall power consumption with little or no impact to
performance. Does not require OS support. </li>
<li><b>HP Static Low Power Mode</b>: Reduces processor speed and power usage.
Guarantees a lower maximum power usage for the system. Performance
impacts will be greater for environments with higher processor
utilization. </li>
<li><b>HP Static High Performance Mode</b>: Processors will run in their
maximum power/performance state at all times regardless of the
OS power managment policy. </li>
<li><b>OS Control Mode</b>: Processors will run in their maximum power/
performance state at all times unless the OS enables' a power
management policy. </li>
</ul>
<p><b>HP Power Profile (Default = Balanced Power and Performance):</b></p>
<p> Values for this BIOS setting can be:</p>
<ul>
<li><b>Balanced Power and Performance</b>: Provides the optimum settings to
maximize power savings with minimal impact to performance for most Operating
Systems and applications.</li>
<li><b>Maximum Performance</b>: Disables all power management options that may
negatively affect performance.</li>
<li><b>Minimum Power Usage</b>: Enables power reduction mechanisms that may
negatively affect performance. This mode will guarantee a lower maximum power
usage by the system. - Maximum Performance: Disables all power management
options that ma negatively affec performance.</li>
</ul>
<p><b>Power Efficiency Mode (Default=Efficiency)</b></p>
<p>Values for this BIOS setting can be:</p>
<ul>
<li><b>Efficiency</b>: Maximize the power efficiency of the server. </li>
<li><b>Performance</b>: Maximize the performance of the server. </li>
<li><b>Custom</b>: Allows the user to customize power and performance related
options individually. </li>
</ul>
<p><b>Intel(R) Hyperthreading Options (Default=Enabled)</b></p>
<p>
This feature allows the enabling/disabling of logical processor cores
on processors supporting Intel Hyper-Threading. </p>
<p><b>Adjacent Sector Prefetch (Default = Enabled):</b></p>
<p>
This BIOS option allows the enabling/disabling of a processor mechanism to
fetch the adjacent cache line within an 128-byte sector that contains
the data needed due to a cache line miss. </p>
<p>
In some limited cases, setting this option to Disabled may improve
performance. In the majority of cases, the default value of Enabled
provides better performance. Users should only disable this option
after performing application benchmarking to verify improved
performance in their environment.</p>
<p><b>Hardware Prefetch (Default = Enabled):</b></p>
<p>
This BIOS option allows allows the enabling/disabling of a processor
mechanism to prefetch data into the cache according to a pattern
recognition algorithm.</p>
<p>
In some limited cases, setting this option to Disabled may improve
performance. In the majority of cases, the default value of Enabled
provides better performance. Users should only disable this option
after performing application benchmarking to verify improved
performance in their environment.</p>
<p><b>Data Reuse (Default = Enabled):</b></p>
<p>
This BIOS option allows the enabling/disabling of the Data
Reuse optimization. </p>
<p>
Enabling this option reduces the frequency of L3 cache updates from
the L1 cache. This may improve performance by reducing the internal
bandwidth consumed by constantly updating L1 cache lines in the L3
cache.</p>
<p>
Since this optimization results in more fetches to main memory, in
some limited cases, setting this option to Disabled may improve
performance. In the majority of cases, the default value of Enabled
provides better performance. Users should only disable this option
after performing application benchmarking to verify improved
performance in their environment.</p>
<p><b>Turbo Mode (Default = Enabled):</b></p>
<p>
Turbo Boost Technology is a processor feature which allows the processor
to transition to a higher frequency than the processor's rate speed if
the processor has available power headroom and is within tempereature
specifications. Disabling this feature will reduce power usage but will
reduce the system's maximum achievable performance under some workloads.
</p>
<p><b>Thermal Configuration (Default = Optimal Cooling):</b></p>
<p>This feature allows the user to select the fan cooling solution for the system.
Values for this BIOS option can be:</p>
<ul>
<li><b>Optimal Cooling</b>: Provides the most efficient solution by
configuring fan speeds to the minimum required to provide adequate
cooling.</li>
<li><b>Increased Cooling</b>: Will run fans at higher speeds to provide
aditional cooling. Increased Cooling should be selected when non-HP
storage controllers are cabled to the embedded hard drive cage, or if
the system is experiencing thermal issues that cannot be resolved in
another manner. This option may also improve performance when Turbo Boost
Technology is used.</li>
</ul>
<p><b>Defer All Transactions Mode (Default = Disabled):</b></p>
<p>
When this option is enabled, front-side bus bandwidth may be increased
on systems with heavy I/O workload because CPU initiated I/O transactions
can be deferred enabling other transactions to make progress while data
is retrieved. However, latency for completing transactions may also
increase. The system's workload will determine which setting will provide
highest performance.</p>
<p> Sets the memory speed and voltage setting for system when there are 2 DIMMs
per channel (2DPC). Values for this BIOS setting can be:</p>
<ul>
</ul>
<p><b>SATA #1 Controller (Default=Auto)</b></p>
<p> Sets the mode for the embedded controller. The values for this BIOS setting
can be:</p>
<ul>
<li><b>Disabled: </b>Disables SATA controller</li>
<li><b>Compatible: </b>Sets controller to IDE Compatiblity mode</li>
<li><b>RAID: </b>Sets controller to RAID mode</li>
<li><b>AHCI: </b>Sets controller to Advanced Host Controller Interface mode</li>
</ul>
]]>
</firmware>
</flagsdescription>
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