I do have��a version #20619 with a VM from get.pharo.org (built Oct 2, jenkins #14731) which gives me 256...

��

��

Is it bad Mr��Stasenko ? (maybe no wonder I had socket issues when scraping a lot of things)

��

Phil

��

On Tue, Oct 8, 2013 at 11:27 AM, Igor Stasenko <siguctua@gmail.com> wrote:

On 7 October 2013 18:36, Norbert Hartl <norbert@hartl.name> wrote:

Am 07.10.2013 um 16:36 schrieb Igor Stasenko <siguctua@gmail.com>:

1 thing.

can you tell me what given expression yields for your VM/image:

Smalltalk vm maxExternalSemaphores

(if it gives you number less than 10000000 then i think i know what is your problem :)

It is��10000000

What would be the problem if it would be smaller?

that just means your VM don't have external object size cap.

I changed the implementation to not have hard limit (the arbitrary large number
is there just to be "compatible" with previous implementation).

This means, that you can actually change in your image the check and completely ignore limits

and just keep growing if it necessary.

Now, since you using VM which don't have a limit, but problem still persists,

it seems like it somewhere else.. :/

i just found that after one merge, my changes get lost

we're just plugged them back in, and it should be back again with newer VMs..

but the problem could be more than just semaphores.. if merge broken this, it may break
many other things, so we need time to check

I try to look at it some more time. I'm using the pharo-vm from the launchpad build. Are the changes supposed to be in this one?

Norbert

Launchpad? You mean ppa? I can't say i remember all the details how changes to VM source
gets into ppa distro, and how fast they get there. @Damien, can you enlighten us?


Well, the VM which i downloaded recently using zero-conf script, having limit back to 256. Just some merge mistake, which now is fixed.. means that couple builds will use limit-based implementation.. but then

it will be back to my implementaiton.

On 7 October 2013 12:31, Norbert Hartl <norbert@hartl.name> wrote:

Am 07.10.2013 um 11:28 schrieb Henrik Johansen <henrik.s.johansen@veloxit.no>:

On Oct 7, 2013, at 11:16 , Norbert Hartl <norbert@hartl.name> wrote:

As I need an image that runs longer than 24 hours I'm looking at some stuff and wonder. Can anybody explain me the rationale for a code like this

maxExternalSemaphores: aSize��

"This method should never be called as result of normal program

execution. If it is however, handle it differently:

- In development, signal an error to promt user to set a bigger size

at startup immediately.

- In production, accept the cost of potentially unhandled interrupts,

but log the action for later review.

See comment in maxExternalObjectsSilently: why this behaviour is

desirable, "

"Can't find a place where development/production is decided.

Suggest Smalltalk image inProduction, but use an overridable temp

meanwhile. "

| inProduction |

self maxExternalSemaphores

ifNil: [^ 0].

inProduction := false.

^ inProduction

ifTrue: [self maxExternalSemaphoresSilently: aSize.

self crTrace: 'WARNING: Had to increase size of semaphore signal handling table due to many external objects concurrently in use';

crTrace: 'You should increase this size at startup using #maxExternalObjectsSilently:';

crTrace: 'Current table size: ' , self maxExternalSemaphores printString]

ifFalse: ["Smalltalk image"

self error: 'Not enough space for external objects, set a larger size at startup!'

"Smalltalk image"]

I have reported this once but got no feedback so I like to have a few opinions.

The report is here:��https://pharo.fogbugz.com/f/cases/10839/

Norbert

The rationale is that inProduction would be some global setting, not yet in place when the code was written���

Excessive simultaneous Semaphore usage is something that should be caught during development, in which case it's better to get an active notification, than having it logged somewhere.

Agreed. But didn't work in my case because it needed roughly 20 hours and an instable remote backend to trigger the problem. And somehow I forgot to install my logger as Transcript so there is no warning message. I saw only dead images in the morning.��

This not satisfactory but on the other hand this type of problems are hard to solve anyway.��My feeling tells me there is more to discover. Sockets resources get unregistered at finalization time but this didn't work either. I would have said that the unlikely situation that no garbage collection ran could be the case. But it can't because in ExternalSemaphoreTable>>#freedSlotsIn:ratherThanIncreaseSizeTo: there is explicit garbage collection.��

If I've understood correctly, it's moot on newer Pharo VM's, where there's no limit on the semtable size, but for legacy code a startup item setting size using maxExternalObjectsSilently: (as suggested in the Warning text), is still a more proper fix than setting inProduction to true and crossing your fingers hoping no signals will be lost during table growth.

Ah, I didn't know about the risk of loosing signals while resizing the table. Thanks for that. Don't get me wrong I wasn't proposing to set inProduction in effect. I don't think that automatically growing resource management is a proper way to design a system. There is always a range of resources you need for your use case. Not setting an upper bound for this just covers leaking behavior.

Norbert

--
Best regards,
Igor Stasenko.

--
Best regards,
Igor Stasenko.