From 3253179b207c2616ce238e2bb765635fe59e6dd2 Mon Sep 17 00:00:00 2001
From: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Date: Thu, 18 Jul 2019 09:58:56 -0400
Subject: [PATCH] [utilities] Fix high CPU usage and slow command collection

commit fc6721ac83c2 ("[Plugin] Terminate running commands when a plugin
exceeds timeout") introduced a polling method to sos_get_command_output()
but it is busy wait, and seems to increase the CPU usage and slow down
AsyncReader significantly.

As a result, a command that outputs much data like journalctl takes
longer time, and the plugin times out.

Inserting a sleep is a possible fix for this.

Resolves: #1732

Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Signed-off-by: Bryn M. Reeves <bmr@redhat.com>
---
 sos/utilities.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sos/utilities.py b/sos/utilities.py
index 1737478f..c3d6ac20 100644
--- a/sos/utilities.py
+++ b/sos/utilities.py
@@ -18,6 +18,7 @@ import errno
 import shlex
 import glob
 import threading
+import time
 
 from contextlib import closing
 from collections import deque
@@ -158,6 +159,7 @@ def sos_get_command_output(command, timeout=300, stderr=False,
                 if poller():
                     p.terminate()
                     raise SoSTimeoutError
+                time.sleep(0.01)
         stdout = reader.get_contents()
         while p.poll() is None:
             pass
@@ -248,7 +250,7 @@ class AsyncReader(threading.Thread):
         # block until command completes or timesout (separate from the plugin
         # hitting a timeout)
         while self.running:
-            pass
+            time.sleep(0.01)
         if not self.binary:
             return ''.join(ln.decode('utf-8', 'ignore') for ln in self.deque)
         else:
-- 
2.21.0