[GHC] #4322: High CPU usage during idle time due to GC

[GHC]

#4322: High CPU usage during idle time due to GC
--------------------------------------+-------------------------------------
  Reporter:  hesselink                |          Owner:         
      Type:  bug                      |         Status:  closed 
  Priority:  normal                   |      Milestone:         
 Component:  Runtime System           |        Version:  6.12.3 
Resolution:  invalid                  |       Keywords:  idle GC
  Testcase:                           |      Blockedby:         
Difficulty:                           |             Os:  MacOS X
  Blocking:                           |   Architecture:  x86    
   Failure:  Runtime performance bug  |  
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Comment(by simonmar):

 I have an idea.  Suppose we had an operation:

 {{{
    idleThread :: Bool -> IO ()
 }}}

 which marks a thread in such a way that if it wakes up it will not cause
 the runtime to think that activity has occurred, which would trigger
 another idle GC.  We would mark the IO manager thread in the same way,
 since all these wakeups involve the IO manager thread too.

 Even with this, I suggest that for your application you probably want to
 set the idle GC to something large like 30s.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4322#comment:7>
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