How to get number of processors in linux with lua api?

Neovim
1

In windows, I can get it with vim.env.NUMBER_OF_PROCESSORS.
But I can’t figure it out how to get it in unix system.
os.execute(“nproc”) returns a wrong value.

if fn.has("win32") > 0 then
    u.num_of_processers = vim.env.NUMBER_OF_PROCESSORS
elseif fn.has("unix") > 0 then
    u.num_of_processers = 4 -- os.execute("nproc") return wrong value
end
2

What does nproc give you run it in the terminal? And what does os.execute("nproc") give you? And which distro are you using?

3

os.execute('nproc') returns its status code, not output. You can use tonumber(vim.fn.system('nproc')) though.

4

Like zeertzjq said, it return 256 (the status code?).
But when I run lua in terminal and run this line, it returns 4 (my number of processors).

5

You could also use vim.loop.cpu_info() it returns a list of objects with model, speed, and times (idle, irq, nice, sys, user). To count the cores you can get the number of items in the list: #vim.loop.cpu_info().

Note that it will be counting with hyper threads, so actual physical core count might be half of whatever number is returned. But that’s the same for nproc as well

6 
local uv = require('luv')

local cpus = uv.available_parallelism()

https://github.com/luvit/luv/blob/master/docs.md#uvavailable_parallelism