crunz: High CPU usage

I used crunz with a php script of sending email (“yiic emailSpool loop” http://cornernote.github.io/yii-email-module). In this script, it’ll fetch spooled email (e.g 10 emails) from db and send them, then sleep 1 second, then next 10 emails,…

The problem is the schedule:run used very high CPU load

Pls look at process 84672

screen shot 2017-07-26 at 3 29 11 pm screen shot 2017-07-26 at 3 30 04 pm

I did try to run yiic emailSpool loop without crunz #yiic emailSpool loop & and it only takes 0.1% cpu (the same result if i put this script to crontab -e) Actually there isn’t many emails to send, most of the time this script hit db get 0 spooled emails, sleep, hit db, 0 emails, sleep, … but the server is always around 90-100% CPU load

About this issue

Original URL
State: closed
Created 7 years ago
Comments: 16

Most upvoted comments

In the end i set probing time to 0,5s, IMO in Cron jobs this time can be set even to 1s. Issue is fixed and released in v1.5.1. Thanks @kinoute for tests and sample code.

PabloKowalczyk on Apr 12, 2018

Now my code (the one I shared earlier) is using less than 1% of my 2009 Mac Mini CPU! I think it’s perfect, thanks!

kinoute on Apr 12, 2018

Thank you @kinoute, your samples was very helpful. IMO the problem was in the EventRunner::ManageStartedEvents(), the while loop doesn’t had any (u)sleep. Could anyone test CPU usage on this version https://github.com/PabloKowalczyk/crunz/tree/fix-high-cpu-usage? In my tests usage reduced from ~30% to ~0,1% 😃

I can do release even today if you confirm that my branch fixed issue.

PabloKowalczyk on Apr 12, 2018

A standard cronjob (like every 5 minutes) linked to a PHP script with a loop inside makes my CPU goes high.

Example (task):

<?php

use Crunz\Schedule;

$schedule = new Schedule();

$schedule->run('/usr/bin/php loop.php')       
         ->everyMinute()
         ->description('Testing a short loop');
         
return $schedule;

loop.php (15 secs are enough to see the high CPU usage)

<?php

for ($i = 1; $i <= 15; $i++) {
    echo $i;
    sleep(1);
}

capture d ecran 2018-04-12 a 11 47 23

Running the loop.php file directly with “php loop.php” doesn’t trigger any increase of the CPU.

Link to the code to reproduce the bug: https://github.com/kinoute/crunz-bug

kinoute on Apr 12, 2018