[asterisk-bugs] [Asterisk 0016158]: [regression] High CPU usage, choppy sound

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16158 
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Reported By:                mustardman
Assigned To:                
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Project:                    Asterisk
Issue ID:                   16158
Category:                   Channels/chan_sip/General
Reproducibility:            random
Severity:                   minor
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           SVN 
JIRA:                       SWP-382 
Regression:                 Yes 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-10-30 19:45 CDT
Last Modified:              2010-01-17 13:29 CST
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Summary:                    [regression] High CPU usage, choppy sound
Description: 
After upgrading from Asterisk 1.6.1.6 to 1.6.1.8 I seem to have a random
problem with high CPU usage.  When making a SIP to SIP call or SIP to
System call Asterisk process CPU usage goes much higher than normal and the
sound get's choppy.  This is somewhat random but occurs fairly regularly,
maybe 50% of the time.

If it happens it happens as soon as a call is answered.  CPU usage
sometimes stays high for minutes and will suddenly go low even though I
didn't do anything.  More often than not it only stays high for a short
period of time and then goes back to normal.

I am running 64bit CentOS 5.4.  Log files and Asterisk CLI -vvvvvvvvvvr
look clean.  

Not sure if this is useful but I will attached a gdb.txt file taken while
it is happening
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 (0116788) mustardman (reporter) - 2010-01-17 13:29
 https://issues.asterisk.org/view.php?id=16158#c116788 
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Little bit of an update.  I came across something that may (may?) explain
what is going on.  Perhaps someone who understands the inner workings of
Asterisk can confirm if this could be a problem.

I am running this on an OpenVZ VPS.  OpenVZ is not compatible with udev
which I believe Asterisk uses in some way.  There are some work arounds for
this.  I was disabling udev and adding these lines on boot up instead:

/sbin/MAKEDEV tty
/sbin/MAKEDEV pty

Searching around a more complete work around which I was NOT doing is to
also add:

/bin/rm -rf /dev/null
/bin/rm -rf /dev/random
/bin/rm -rf /dev/tty*
/bin/rm -rf /dev/pty*
/bin/mknod /dev/null c 1 3
/bin/mknod /dev/random c 1 8

So I am wondering if Asterisk was trying to use /dev/null and/or
/dev/random and was not able to which could cause the CPU spike? 

Issue History 
Date Modified    Username       Field                    Change               
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2010-01-17 13:29 mustardman     Note Added: 0116788                          
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