[Varnish] #501: Stats variable to monitor how many threads are actually doing something (n_wrk_busy): busy threads monitoring

[Varnish]

#501: Stats variable to monitor how many threads are actually doing something
(n_wrk_busy): busy threads monitoring
-------------------------------------+--------------------------------------
 Reporter:  stockrt                  |        Owner:  phk       
     Type:  enhancement              |       Status:  closed    
 Priority:  normal                   |    Milestone:  Later     
Component:  varnishd                 |      Version:  trunk     
 Severity:  normal                   |   Resolution:  worksforme
 Keywords:  busy threads monitoring  |  
-------------------------------------+--------------------------------------
Changes (by phk):

  * status:  new => closed
  * resolution:  => worksforme


Comment:

 We revisted the oldest tickets on the bug-wash today, and finally(!)
 made our mind up about this one:

 The central concern here is that the locking necessary for such a counter
 would be expensive, performance wise, because it would serialize all
 sessions on that lock.

 The plans presently is to make the thread-pools even more independent and
 as a result of that, we will get per-thread-pool statistics.  For each
 thread-pool, having a counter of number of busy treads is actually pretty
 cheap, so that we can do.

 What is needed then is for libvarnishapi or varnishstat to tally up the
 global sum for all the threadpools.

 I'm closing this ticket, because it does not really serve any function
 going forward, seeing that the ultimate solution is much different from
 what is proposed.

 Sorry for taking so long to resolve this.

-- 
Ticket URL: <http://www.varnish-cache.org/trac/ticket/501#comment:7>
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