[PATCH] Have fedabipkgdiff sleep while waiting for abipkgdiff

[PATCH] Have fedabipkgdiff sleep while waiting for abipkgdiff

[Ben Woodard]

While running tests, I noticed that python was consuming a huge amount
of CPU. Frank ch Eiger fche@redhat.com located the problem and pointed
out that python was continiously polling for abipkgdiff's
completion. For small packages, the time to completion can be less
than a second but some packages can take literally hours to
analyze. Having python spinning in such a tight loop is unnecessary. I
added a small sleep to this loop with a bit of backoff. Vanessa Sochat
helped with examples of how to fix the python code.

     * tools/fedabipkgdiff add sleep while waiting for subprocess
     completion.

Signed-off-by: Ben Woodard <woodard@redhat.com>
---
 tools/fedabipkgdiff | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/fedabipkgdiff b/tools/fedabipkgdiff
index db23d5a3..2867a8d0 100755
--- a/tools/fedabipkgdiff
+++ b/tools/fedabipkgdiff
@@ -20,6 +20,7 @@ import shutil
 import six
 import subprocess
 import sys
+import time
 
 from collections import namedtuple
 from itertools import chain
@@ -1187,9 +1188,14 @@ def abipkgdiff(cmp_half1, cmp_half2):
     # then we get its output.
     #
 
+    sleeptime = 0.2
     while True:
         if proc.poll() != None:
             break
+        time.sleep(sleeptime)
+        # cap the sleep time at 1.6s
+        if sleeptime < 2.0:
+            sleeptime = sleeptime * 2
 
     stdout = ''.join(proc.stdout.readlines())
     stderr = ''.join(proc.stderr.readlines())
-- 
2.31.1

Re: [PATCH] Have fedabipkgdiff sleep while waiting for abipkgdiff

[Dodji Seketeli]

Hello,

Ben Woodard via Libabigail <libabigail@sourceware.org> a écrit:

> While running tests, I noticed that python was consuming a huge amount
> of CPU. Frank ch Eiger fche@redhat.com located the problem and pointed
> out that python was continiously polling for abipkgdiff's
> completion. For small packages, the time to completion can be less
> than a second but some packages can take literally hours to
> analyze. Having python spinning in such a tight loop is unnecessary. I
> added a small sleep to this loop with a bit of backoff. Vanessa Sochat
> helped with examples of how to fix the python code.
>
>      * tools/fedabipkgdiff add sleep while waiting for subprocess
>      completion.

Thanks Ben!

I have just slightly edited the ChangeLog to make it comply with the
rules (i.e, adding the name of the changed function).  I have also
updated the copyright year that is outdated.

> Signed-off-by: Ben Woodard <woodard@redhat.com>

Please find below the patch that was applied to mainline.

Cheers,

From 1174a9f0c428149e21115401c44c648b3aaa2678 Mon Sep 17 00:00:00 2001
From: Ben Woodard <woodard@redhat.com>
Date: Tue, 28 Mar 2023 12:52:28 -0700
Subject: [PATCH] Have fedabipkgdiff sleep while waiting for abipkgdiff

While running tests, I noticed that python was consuming a huge amount
of CPU. Frank Eigler located the problem and pointed
out that python was continiously polling for abipkgdiff's
completion. For small packages, the time to completion can be less
than a second but some packages can take literally hours to
analyze. Having python spinning in such a tight loop is unnecessary. I
added a small sleep to this loop with a bit of backoff. Vanessa Sochat
helped with examples of how to fix the python code.

	* tools/fedabipkgdiff (abipkgdiff): add sleep while waiting for
	subprocess completion. Also, update copyright year notice to 2023.

Signed-off-by: Ben Woodard <woodard@redhat.com>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
---
 tools/fedabipkgdiff | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/fedabipkgdiff b/tools/fedabipkgdiff
index db23d5a3..86bf0048 100755
--- a/tools/fedabipkgdiff
+++ b/tools/fedabipkgdiff
@@ -3,7 +3,7 @@
 # -*- coding: utf-8 -*-
 # -*- Mode: Python
 #
-# Copyright (C) 2013-2016 Red Hat, Inc.
+# Copyright (C) 2013-2023 Red Hat, Inc.
 #
 # Author: Chenxiong Qi
 
@@ -20,6 +20,7 @@ import shutil
 import six
 import subprocess
 import sys
+import time
 
 from collections import namedtuple
 from itertools import chain
@@ -1187,9 +1188,14 @@ def abipkgdiff(cmp_half1, cmp_half2):
     # then we get its output.
     #
 
+    sleeptime = 0.2
     while True:
         if proc.poll() != None:
             break
+        time.sleep(sleeptime)
+        # cap the sleep time at 1.6s
+        if sleeptime < 2.0:
+            sleeptime = sleeptime * 2
 
     stdout = ''.join(proc.stdout.readlines())
     stderr = ''.join(proc.stderr.readlines())
-- 
2.39.2


-- 
		Dodji