# Booting kernel without SMP support

**URL:** <https://linux-tips.com/t/booting-kernel-without-smp-support/79>\
**Category:** Kernel\
**Created:** [February 19, 2015, 2:32pm UTC](https://linux-tips.com/t/booting-kernel-without-smp-support/79 "2015-02-19T14:32:47Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Greg](https://linux-tips.com/letter_avatar_proxy/v4/letter/g/71c47a/32.png) [@Greg](https://linux-tips.com/u/Greg)\
**Post date:** [February 19, 2015, 2:32pm UTC](https://linux-tips.com/t/booting-kernel-without-smp-support/79/1 "2015-02-19T14:32:47Z")

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We have a program which opens a lot of threads make some time critical calculations. I wonder about SMP scheduling effect. It is possible to boot Linux kernel with `nosmp` or `maxcpus=0` argument to disable multiple processing support. But is there any way to make this without rebooting the system?

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<div class="post-metadata">

**Author:** ![MisterNo](https://linux-tips.com/user_avatar/linux-tips.com/misterno/32/55_2.png) [@MisterNo](https://linux-tips.com/u/MisterNo)\
**Post date:** [February 19, 2015, 2:40pm UTC](https://linux-tips.com/t/booting-kernel-without-smp-support/79/2 "2015-02-19T14:40:23Z")

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It is possible to set a CPU to offline or online mode through `sysfs` while system running.

You can set `online` variable to `0` for each of the cpu cores which you want to make offline:

```
echo 0 > /sys/devices/system/cpu/cpu2/online

```

Think about what will be happen if you set all of the cpu cores to offline 😉