multithreading - How can Python continuously fill multiple threads of subprocess? -

i'm running app, foo, on linux. bash script/terminal prompt, application runs multi-threaded command:

$ foo -config x.ini -threads 4 < inputfile 

system monitor , top report foo averages 380% cpu load (quad-core machine). i've recreated functionality in python 2.6x with:

proc = subprocess.popen("foo -config x.ini -threads 4", \         shell=true, stdin=subprocess.pipe, \         stdout=subprocess.pipe, stderr=subprocess.pipe) mylist = ['this','is','my','test','app','.'] line in mylist:     txterr = ''     proc.stdin.write(line.strip()+'\n')     while not proc.poll() , not txterr.count('finished'):         txterr += subproc.stderr.readline()     print proc.stdout.readline().strip(), 

foo runs slower , top reports cpu load of 100%. foo runs fine shell=false, still slow:

proc = subprocess.popen("foo -config x.ini -threads 4".split(), \         shell=false, stdin=subprocess.pipe, \         stdout=subprocess.pipe, stderr=subprocess.pipe) 

is there way have python subprocess continuously fill threads?

if python script doesn't feed foo process fast enough offload reading stdout, stderr threads:

from queue import empty, queue subprocess import pipe, popen threading import thread  def start_thread(target, *args):     t = thread(target=target, args=args)     t.daemon = true     t.start()     return t  def signal_completion(queue, stderr):     line in iter(stderr.readline, ''):         if 'finished' in line:            queue.put(1) # signal completion     stderr.close()  def print_stdout(q, stdout):     """print stdout upon receiving signal."""     text = []     line in iter(stdout.readline, ''):         if not q.empty():            try: q.get_nowait()                           except empty:                text.append(line) # queue empty            else: # received completion signal                              print ''.join(text),                text = []                q.task_done()         else: # buffer stdout until task finished             text.append(line)     stdout.close()     if text: print ''.join(text), # print rest unconditionally  queue = queue() proc = popen("foo -config x.ini -threads 4".split(), bufsize=1,              stdin=pipe, stdout=pipe, stderr=pipe) threads =  [start_thread(print_stdout, queue, proc.stdout)] threads += [start_thread(signal_completion, queue, proc.stderr)]  mylist = ['this','is','my','test','app','.'] line in mylist:     proc.stdin.write(line.strip()+'\n') proc.stdin.close() proc.wait() t in threads: t.join() # wait stdout