[asterisk-bugs] [DAHDI-linux 0017620]: High CPU utlization by ksoftirqd since enabling of internal timing in r8053

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=17620 
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Reported By:                seanbright
Assigned To:                sruffell
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Project:                    DAHDI-linux
Issue ID:                   17620
Category:                   dahdi (the module)
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     assigned
JIRA:                        
Reviewboard Link:            
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Date Submitted:             2010-07-10 13:22 CDT
Last Modified:              2010-07-12 13:45 CDT
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Summary:                    High CPU utlization by ksoftirqd since enabling of
internal timing in r8053
Description: 
Running on a Dell PowerEdge R610 with 2 TCE400B transcoder cards.  Also
reproducible on a Dell PowerEdge T310 with no DAHDI hardware at all.

'top' shows ksoftirqd taking up 30-60% of CPU once dahdi is loaded and
load average rises, even without asterisk loaded.  Before r8053, this
problem does not manifest.

I have marked this bug as affecting 2.3.0, but I have tested with
dahdi-linux/trunk and it is still occurring.

Please let me know what other information I can provide.
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 (0124520) svnbot (reporter) - 2010-07-12 13:45
 https://issues.asterisk.org/view.php?id=17620#c124520 
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Repository: dahdi
Revision: 8868

U   linux/trunk/drivers/dahdi/dahdi-base.c
U   linux/trunk/drivers/dahdi/dahdi_dummy.c

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r8868 | sruffell | 2010-07-12 13:45:02 -0500 (Mon, 12 Jul 2010) | 12 lines

dahdi: Explicitly ensure we don't schedule a timer for the current tick.

As best as I can tell, when CONFIG_NO_HZ is set along with CONFIG_HZ <
250, it
is possible for the system timer to exceed MAX_SOFTIRQ_RESTART. Tony
Mountifield alluded that this might be a problem in the below mailing list
posting, but when I was originally testing, I wasn't using CONFIG_NO_HZ
and HZ
< 250.

http://www.mail-archive.com/asterisk-dev@lists.digium.com/msg37384.html

(closes issue https://issues.asterisk.org/view.php?id=17620)
Reported by: seanbright
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http://svn.digium.com/view/dahdi?view=rev&revision=8868 

Issue History 
Date Modified    Username       Field                    Change               
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2010-07-12 13:45 svnbot         Checkin                                      
2010-07-12 13:45 svnbot         Note Added: 0124520                          
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