Re: [Pharo-project] Too many semaphores, image blocked

[Henrik Sperre Johansen]

On 20.10.2011 15:30, Igor Stasenko wrote:
2011/10/20 Janko Mivšek<janko.miv...@eranova.si>:
Hi guys,
I'm measuring how my image is breathing through the time and what is
interesting is how nr. of Semaphore instances is variating through the
time. Every hour just before snapshot I report nr of instances, see last
10 hours:

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   259 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   274 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   312 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   356 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   346 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   141 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   22 Processes
   310 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   26 Processes
   79 Semaphores

** image state:
   0 HTTPCommections
   4 Sockets
   20 Processes
   300 Semaphores


Well, the number of semaphores tells nothing because not all of them
serve for sockets.

There are 3 semaphores per socket. So, if you have 4 sockets, there
should be 12 external objects.
Of course not counting others, which is there for other purposes.

Could you add following to report:

Socket registry size
StandardFileStream registry size
(ExternalSemaphoreTable unprotectedExternalObjects reject: #isNil) size
There's something wrong with startup/shutdown list, at least with my 
Pharo 1.4 image...
The InputEventFetcher's shutdown/startup methods are called twice when 
you save, thus you end up with an extra semaphore in the table whenever 
you save.

Janko just runs into the consequences of this faster as he saves frequently.

Cheers,
Henry

View transcript when saving with InputEventFetcher doing logging like:

shutDown
    self crLog: 'Shutdown called!'.
    self terminateEventLoop.
    inputSemaphore ifNotNil: [|pre post|
        pre := (ExternalSemaphoreTable unprotectedExternalObjects 
select: [:each | each notNil]) size.
        Smalltalk unregisterExternalObject: inputSemaphore.
        post := (ExternalSemaphoreTable unprotectedExternalObjects 
select: [:each | each notNil]) size.
        pre = post ifTrue: [self logCr: 'Tried unregistering 
inputSemaphore, but still there!']]

startUp
    self crLog: 'Startup called!'.
    inputSemaphore := Semaphore new.
    self primSetInputSemaphore: (Smalltalk registerExternalObject: 
inputSemaphore).
    inputSemaphore initSignals.
    self installEventLoop