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Bug 305831

Summary: excessive cpu usage in recovery code
Product: Red Hat Enterprise Linux 5 Reporter: David Teigland <teigland>
Component: kernelAssignee: David Teigland <teigland>
Status: CLOSED INSUFFICIENT_DATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: low Docs Contact:
Priority: low    
Version: 5.1CC: ccaulfie, cluster-maint, djansa
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Hardware: All   
OS: Linux   
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Last Closed: 2009-05-01 19:13:47 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description David Teigland 2007-09-25 18:51:04 UTC 
Description of problem:

The dlm recovery code calls schedule() in a lot of lock loops
to prevent:

1) the softlock watchdog from going off
2) openais cluster membership messages for being delayed past
   the configured timeout

We want to investigate:

- will cond_resched() work as well, and more efficiently than schedule()?
  (I expect so)
- exactly what loops are taking so long (watchdog is 10 sec) and why?
  are there really that many locks and/or are we doing that much work
  on each one that it can take 10 sec?
- why does this seem to appear on ia64 regularly and other arch's rarely?

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Comment 1 David Teigland 2008-06-24 17:25:27 UTC 
Dean, do you still get softlockups on ia64?