Haskell affinity

Affinity.hs

{-# LANGUAGE ForeignFunctionInterface #-}

module System.Posix.Affinity (setAffinityOS) where

import Control.Monad
import Foreign
import Foreign.C
import System.IO.Error

foreign import ccall unsafe "pin_pthread" pin_pthread :: CInt -> IO Errno

setAffinityOS :: Int -> IO ()
setAffinityOS cpu = do
  err <- pin_pthread $ fromIntegral cpu
  when (err /= eOK) $
    ioError $ errnoToIOError "setAffinityOS" err Nothing Nothing

pin.c

#define _GNU_SOURCE
#include <pthread.h>
#include <sched.h>
#include <stdlib.h>
#include "pin.h"

int pin_pthread(int cpu) {
  cpu_set_t cs;
  pthread_t thread;

  thread = pthread_self();

  CPU_ZERO(&cs);
  CPU_SET(cpu, &cs);
  return pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cs);
}