How-To Geek
Display Number of Processors on Linux
If you’ve just upgraded your Linux box, or you are wondering how many processors a remote server has, there’s a quick and dirty command you can use to display the number of processors.
On Linux, /proc/cpuinfo contains all of the processor information for all current processors in your computer. This will include the speed, the amount of on-chip cache, processor type, and how many cores.
Here’s the command:
cat /proc/cpuinfo | grep processor | wc -l
The command just looks in the /proc/cpuinfo file, pulls out the number of lines containing the word “processor” and passes them into wc (word count), which returns a count of the CPUs in the system.
Here’s what it returned on my remote server:
[root@root]# cat /proc/cpuinfo | grep processor | wc -l
4
Note that if you have a dual-core processor, it will return each core as a separate processor. You can look at the full output of cat /proc/cpuinfo to see if the chips are dual-core.
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- By The Geek on 02/22/07
Comments (10)
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Hi,
this will give you the same result and saves you having to type a couple of characters
grep processor /proc/cpuinfo |wc -l
This will save you a pipe
grep -c processor /proc/cpuinfo
Won’t this count CPUs with hyperthreading twice? My computer has one Pentium 4 (Prescott) CPU, but has two processor entries in cpuinfo.
Well… Sorry to say that it doesn’t work most of the time. Beside multithreadin processors, It is common that entry on a single processor has multiple occurence of word “processor” (both in the procesor identifier and model name.
On my ancient pemtium M laptop it reports 2 processors because ist modelname is “Intel(R) Pentium(R) M processor 1.73GHz”.
This might help:
grep -c ^processor /proc/cpuinfo
To get the count of physical CPUs, this works by counting the unique physical ids
grep “physical id” /proc/cpuinfo |sort -u|wc -l
This comment I wrote may also help you (it’s actually for Linux): http://www.howtogeek.com/howto/solaris/get-the-processor-type-on-solaris/#comment-64380
@Ron
With a single-core CPU, “physical id” will return zero rows
I’ve ended up with the following admittedly clumsy solution:
grep core\ id /proc/cpuinfo | grep -c \ 0$ | grep ^0$ >> /dev/null && grep -c processor /proc/cpuinfo || grep core\ id /proc/cpuinfo | grep -c \ 0$
For physical CPU’s you could also do:
dmidecode | grep CPU
Had a bit of an exception on my machine – the “grep processor” command found the following 2 lines:
processor : 0
model name : Intel(R) Pentium(R) M processor 1.80GHz
(the command incorrectly returned ’2′ as my number of processors.)
It needs a caret before ‘processor’, so that it only finds it at the beginning of the line: cat /proc/cpuinfo | grep “^processor” | wc -l
This will give you the physical core count:
fgrep -m 1 ‘cpu cores’ /proc/cpuinfo | cut -d ‘ ‘ -f 3