The lua-affinity module for Lua is a thin wrapper around Linux schedutils calls sched_setaffinity(2) and sched_getaffinity(2). It also contains a Lua interface for creating and manipulating the cpu_set_t CPU masks used by the interface.

Creating cpu_set_t objects:

local cpu_set =  require 'affinity.cpuset'
c = cpu_set.new("0-1,4")              -- create cpu_set from cstr list
x = cpu_set.new("0xf0")               -- create a cpu_set from hex strin
v = cpu_set.new()                     -- Empty cpu_set
m = cpu_set.new("00000000,0000000f")  -- Linux bit string format

Operators:

• Equals: s1 == s2: test for s1 equals s2 (same CPUs in set)
• Addition: s1 + s1: Return the union of s1 and s2 (returns copy)
• Deletion: (s1 - s2): Unset CPUs in s2 from s1
• Length: (#s1): Return number of CPUs set in cpuset
• Tostring: (tostring (s1)): Convert s1 to cstr type CPU list (0-1,4)
• Concatenation (..): string concatenation as above (implied tostring)

Named methods:

• s:set (i,...): Explicitly set CPU or CPUs
• s:clr (i,...): Explicitly clear CPU or CPUs
• s:isset (i): Return true if CPUi set in s
• s:zero (): Clear all cpus from set s
• s:first (): Return first set CPU in s
• s:last (): Return last set CPU in s
• s:count (): Return number of CPUs in the set
• s:weight (): Return number of CPUs in the set
• s:tohex (): Return hex string representation of s (linux bitstring format)
• s:union (s2): Set all bits in s1 that are set in s1 or s2
• s:intersect (s2): unset bits in s1 that are not set in s2
• s:is_in (s2): Is set s contained within s2
• s:contains (s2): Is set s2 contained within set s
• s:expand ([fn]): Expand s into a table, optionally using function fn as a filter.

Iterator:

• s:setbits (): Iterate over all set bits in s:

   s = cpuset.new ("0xf001")
   for i in s:setbits () do
       print (i)
   end
  

• s[i]: Return true if CPU i is set in cpu_set otherwise false
• s[i] = 0: Unset CPU i in s
• s[i] = 1: Set CPU i in s

local affinity = require 'affinity'
local s1 = affinity.getaffinity ()
print (s1)
local s2 = affinity.cpuset.new ("0-1")
local rc, err = affinity.setaffinity (s2)