CPU, vCPU, Core Counts and the Socket-Core-vCPU Mapping in Solaris

It should be easy to find this information just by running an OS command. However for some reason it ain't the case as of today. The user must know few details about the underlying hardware and run multiple commands to figure out the exact number of physical processors, cores etc.,

For the benefit of our customers, here is a simple shell script that displays the number of physical processors, cores, virtual processors, cores per physical processor, number of hardware threads (vCPUs) per core and the virtual CPU mapping for all physical processors and cores on a Solaris system (SPARC or x86/x64).

This script showed valid output on recent T-series, M-series hardware as well as on some older hardware - Sun Fire 4800, x4600. Due to the changes in the output of cpu_info over the years, it is possible that the script may return incorrect information in some cases. Since it is just a shell script, tweak the code as you like. The script can be executed by any OS user.

# vi /root/showcpucount.sh

--------------------------------------- CUT HERE ------------------------------------------- 
#!/bin/bash

/usr/bin/kstat -m cpu_info | egrep "chip_id|core_id|module: cpu_info" > /var/tmp/cpu_info.log

nproc=`(grep chip_id /var/tmp/cpu_info.log | awk '{ print $2 }' | sort -u | wc -l | tr -d ' ')`
ncore=`(grep core_id /var/tmp/cpu_info.log | awk '{ print $2 }' | sort -u | wc -l | tr -d ' ')`
vproc=`(grep 'module: cpu_info' /var/tmp/cpu_info.log | awk '{ print $4 }' | sort -u | wc -l | tr -d ' ')`

nstrandspercore=$(($vproc/$ncore))
ncoresperproc=$(($ncore/$nproc))

speedinmhz=`(/usr/bin/kstat -m cpu_info | grep clock_MHz | awk '{ print $2 }' | sort -u)`
speedinghz=`echo "scale=2; $speedinmhz/1000" | bc`

echo "Total number of physical processors: $nproc"
echo "Number of virtual processors: $vproc"
echo "Total number of cores: $ncore"
echo "Number of cores per physical processor: $ncoresperproc"
echo "Number of hardware threads (strands or vCPUs) per core: $nstrandspercore"
echo "Processor speed: $speedinmhz MHz ($speedinghz GHz)"

# now derive the vcpu-to-core mapping based on above information #

echo -e "\n** Socket-Core-vCPU mapping **"
let linenum=2

for ((i = 1; i <= ${nproc}; ++i ))
do
        chipid=`sed -n ${linenum}p /var/tmp/cpu_info.log | awk '{ print $2 }'`
        echo -e "\nPhysical Processor $i (chip id: $chipid):"

        for ((j = 1; j <= ${ncoresperproc}; ++j ))
        do
                let linenum=($linenum + 1)
                coreid=`sed -n ${linenum}p /var/tmp/cpu_info.log | awk '{ print $2 }'`
                echo -e "\tCore $j (core id: $coreid):"

                let linenum=($linenum - 2)
                vcpustart=`sed -n ${linenum}p /var/tmp/cpu_info.log | awk '{ print $4 }'`

                let linenum=(3 * $nstrandspercore + $linenum - 3)
                vcpuend=`sed -n ${linenum}p /var/tmp/cpu_info.log | awk '{ print $4 }'`

                echo -e "\t\tvCPU ids: $vcpustart - $vcpuend"
                let linenum=($linenum + 4)
        done
done

rm /var/tmp/cpu_info.log
--------------------------------------- CUT HERE -------------------------------------------

# prtdiag | head -1
System Configuration:  Sun Microsystems  sun4u SPARC Enterprise M4000 Server

# ./showcpucount
Total number of physical processors: 4
Number of virtual processors: 32
Total number of cores: 16
Number of cores per physical processor: 4
Number of hardware threads (strands or vCPUs) per core: 2
Processor speed: 2660 MHz (2.66 GHz)

** Socket-Core-vCPU mapping **

Physical Processor 1 (chip id: 1024):
        Core 1 (core id: 0):
                vCPU ids: 0 - 1
        Core 2 (core id: 2):
                vCPU ids: 2 - 3
        Core 3 (core id: 4):
                vCPU ids: 4 - 5
        Core 4 (core id: 6):
                vCPU ids: 6 - 7

Physical Processor 2 (chip id: 1032):
        Core 1 (core id: 8):
                vCPU ids: 8 - 9
        Core 2 (core id: 10):
                vCPU ids: 10 - 11
        Core 3 (core id: 12):
                vCPU ids: 12 - 13
        Core 4 (core id: 14):
                vCPU ids: 14 - 15

Physical Processor 3 (chip id: 1040):
        Core 1 (core id: 16):
                vCPU ids: 16 - 17
        Core 2 (core id: 18):
                vCPU ids: 18 - 19
        Core 3 (core id: 20):
                vCPU ids: 20 - 21
        Core 4 (core id: 22):
                vCPU ids: 22 - 23

Physical Processor 4 (chip id: 1048):
        Core 1 (core id: 24):
                vCPU ids: 24 - 25
        Core 2 (core id: 26):
                vCPU ids: 26 - 27
        Core 3 (core id: 28):
                vCPU ids: 28 - 29
        Core 4 (core id: 30):
                vCPU ids: 30 - 31