Home

cpu

Linux cpu processor cores and threads

Fri, 11/12/2010 - 12:26 — sandip

/proc/cpuinfo has the info you need to identify the number of processors, cores and threads.

To get the total number of processors/cpu cores:

grep -c processor /proc/cpuinfo

Total number of physical cpus:

grep "physical id" /proc/cpuinfo | sort -u | wc -l

Number of cores per cpu:

grep "cores" /proc/cpuinfo | sort -u

To check if hyperthreading is enabled:

grep "cores\|siblings" /proc/cpuinfo | sort -u

If siblings is a multiple of cores then hyperthreading is enabled.

Run process with least cpu and IO priority

Tue, 08/24/2010 - 14:38 — sandip

Below is command to run process with the least CPU and IO priority.

nice -n 19 ionice -c 3 <command>

You could also include the same in the beginning of the script:

#!/bin/bash
# Make process nice
renice +19 -p $$ >/dev/null 2>&1
ionice -c3 -p $$ >/dev/null 2>&1

References:

Determine cpu bit

Sat, 07/04/2009 - 19:18 — sandip

You can try this to find out if your CPU/Processor is 32 bit or 64 bit:

cat /proc/cpuinfo | grep flags | grep lm

lm means Long Mode = 64 bit CPU

Also:

getconf LONG_BIT

Should display 32 or 64.

mysql if using too much CPU of my VPS.

Wed, 05/06/2009 - 10:49 — jonitas

Can anybody help me?
Basically my app is for an email marketing, so using a while statement its reads from a db (mysam) and make updates

Thank in advance!!

This is the info about my VPS (when typing )
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
Mem: 1206272 kB
OS: CentOS release 5.3 (Final)
Mysql: 5.0.45-log

This is my my.cnf:
[client]
port = 3306
socket = /var/lib/mysql/mysql.sock

###The MySQL server
[mysqld]
set-variable=local-infile=0

Check if cpu supports 64 bit

Sun, 04/22/2007 - 00:56 — sandip

If the below produces lm (long mode) flags, then the cpu has support for x86_64 architecture.

# grep lm /proc/cpuinfo

I have seen quite a few dedicated servers with support for x86_64 architecture, but i386 installed instead.

When doing a `uname -a`, the output misleads you to think that x86_64 is not supported. Such machines do not fully utilize the hardware resources and decreases performance of you box.

Comment