[Varnish] #572: Fix for: Create worker thread failed 11 Resource temporarily unavailable (Thread Problem on Linux)

[Varnish]

#572: Fix for: Create worker thread failed 11 Resource temporarily unavailable
(Thread Problem on Linux)
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 Reporter:  whocares     |        Owner:  phk  
     Type:  enhancement  |       Status:  new  
 Priority:  normal       |    Milestone:       
Component:  varnishd     |      Version:  trunk
 Severity:  normal       |   Resolution:       
 Keywords:               |  
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Comment (by kb):

 The "easy" way to avoid the 8MB or 10MB default stacksize penalty is to
 run "ulimit -s 1024" to reduce the default stack to 1MB in the same
 process before starting varnishd.  Putting the ulimit in the start script
 is the easier way.

 But some threads will have a higher stack requirement than others.  The
 primary threads that are required for scale on Varnish (AFIACT) are the
 worker and backend threads, so it made sense to me that reducing the usage
 of these is most important, and that it was safest to only reduce the
 stack size of these threads.

 A few months ago, I wrote the attached patch which adds a varnishd
 parameter to set the stack size for worker and backend threads.  I've been
 using it in production for months as "-p thread_pool_stacksize=256".
 256KB is the smallest safe stack size on x86_64 in my experience, and
 allows for plenty of threads.

 This patch is against 2.0.4, but it applies without fuzz to trunk at 4339.

 Ken

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Ticket URL: <http://varnish.projects.linpro.no/ticket/572#comment:1>
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