Disabling and enabling interactive mode on Torque

To disable interactive mode for a selected queue in Torque, it is very simple to implement, you just fire a command

# qmgr -c 'set queue queue_name disallowed_types = interactive'

To remove this attribute , use the qmgr -c unset command.

# qmgr -c 'unset queue queue_name disallowed_types'

For more information, see  Using qmgr to remove a queue attribute

OFED Performance Micro-Benchmark Latency Test

Open Fabrics Enterprise Distribution (OFED) has provided simple performance micro-benchmark has provided a collection of tests written over uverbs. The notes taken from OFED Performance Tests README

1. The benchmark uses the CPU cycle counter to get time stamps without a context switch.
2. The benchmark measures round-trip time but reports half of that as one-way latency. This means that it may not be sufficiently accurate for asymmetrical configurations.
3. Min/Median/Max results are reported.
   The Median (vs average) is less sensitive to extreme scores.
   Typically, the Max value is the first value measured Some CPU architectures
4. Larger samples only help marginally. The default (1000) is very satisfactory.   Note that an array of cycles_t (typically an unsigned long) is allocated once to collect samples and again to store the difference between them.   Really big sample sizes (e.g., 1 million) might expose other problems with the program.

On the Server Side

# ib_write_lat -a

On the Client Side

# ib_write_lat -a Server_IP_address

For more information, do take a look at OFED Performance Micro-Benchmark Latency Test

Enabling CPU Scaling for Dual socket.

My earlier blog entry that shutting the cpuspeed daemon somehow only impact the first socket, but the second socket is still running at a reduced speed. There is a write-ups which was obtained from Experts-Exchange "Avoiding CPU speed scaling in modern Linux distributions. Running CPU at full speed Tips."

Firstly, do what was written at Disabling CPU speed scaling in CentOS 5

On CentOS 5, you may want to use the script and place it at /etc/init.d/cpuperf.

#! /bin/bash
#
# cpuperf sets cpu govermor
#
# chkconfig: 2345 10 90
#
# description: Set the CPU Frequency Scaling governor to "performance"
#
### BEGIN INIT INFO
# Provides: $ondemand
### END INIT INFO

PATH=/sbin:/usr/sbin:/bin:/usr/bin

case "$1" in
    start)
        for CPUFREQ in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
        do
                [ -f $CPUFREQ ] || continue
                echo -n performance > $CPUFREQ
        done
        ;;
    restart|reload|force-reload)
        echo "Error: argument '$1' not supported" >&2
        exit 3
        ;;
    stop)
        ;;
    *)
        echo "Usage: $0 start|stop" >&2
        exit 3
        ;;
esac                                    

Type the command and you will see that the CPUSpeed are all at performance level.

# grep -E '^model name|^cpu MHz' /proc/cpuinfo

Understanding the Infiniband Subnet

Intel has published a easy-to-understand article on Infiniband Subnetting. "Understanding the InfiniBand Subnet Manager"

From the article:

The InfiniBand subnet manager (OpenSM) assigns Local IDentifiers (LIDs) to each port connected to the InfiniBand fabric, and develops a routing table based off of the assigned LIDs. 
....
....
A typical InfiniBand installation using the OFED package will run the OpenSM subnet manager at system start up after the OpenIB drivers are loaded. This automatic OpenSM is resident in memory, and sweeps the InfiniBand fabric approximately every 5 seconds for new InfiniBand adapters to add to the subnet routing tables. This usage will be sufficient for most installations, and can be controlled using the following commands:

/etc/init.d/opensmd start
/etc/init.d/opensmd stop
/etc/init.d/opensmd restart
/etc/init.d/opensmd status

For more information, read the article.

Software Updates for critical vulnerability in Java 7 is available

Oracle has released an emergency software update today to fix a vulnerability that is exploited by a zero-day Trojan horse called Mal/JavaJar-B, which was already identified as attacking Windows, Linux and Unix systems and being distributed in exploit kits "Blackhole" and "NuclearPack," making it far more convenient to attackers. More information of Update Release  of the Software Update.

More Information on Java 7 Vulnerability:

1. Oracle Java 7 Security Manager Bypass Vulnerability