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[Help-smalltalk] Random exceptions terminating root process
From: |
Tony Garnock-Jones |
Subject: |
[Help-smalltalk] Random exceptions terminating root process |
Date: |
Tue, 08 Jan 2008 13:44:46 +0000 |
User-agent: |
Thunderbird 1.5.0.14 (X11/20071210) |
Hi,
Here's the test case code I mentioned earlier. It's probably my code
that's at fault, rather than the VM, but it's still very strange behaviour.
When you run TerminationExperiment's #run, it can sometimes reach
several tens of thousands of iterations of busyLoop before faulting, but
will often fault before 20,000 iterations have completed on my machine.
When you run #run2, things behave as I would have expected them to
behave. No faulting occurs, and the process is sensibly terminated.
Here's a selection of some of the faults I see from #run after several
seconds. Each comes at the end of a single run of the script, as attached.
Object: '' error: Invalid argument : must be a SmallInteger
SystemExceptions.WrongClass(Exception)>>signal
SystemExceptions.WrongClass class>>signalOn:mustBe:
SystemExceptions.WrongClass class>>signalOn:mustBe:
String(Object)>>checkIndexableBounds:put:
String>>at:put:
String class(ArrayedCollection class)>>with:
Character>>asString
[] in TextCollector>>showCr:
[] in Semaphore>>critical:
BlockClosure>>ensure:
Semaphore>>critical:
TextCollector>>showCr:
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
Object: nil error: did not understand #generality
MessageNotUnderstood(Exception)>>signal
UndefinedObject(Object)>>doesNotUnderstand: #generality
SmallInteger>>+
FileStream(FileDescriptor)>>write:from:to:
FileStream>>flush
FileStream(Stream)>>nextPutAllFlush:
TextCollector>>primNextPutAll:
[] in TextCollector>>showCr:
[] in Semaphore>>critical:
BlockClosure>>ensure:
Semaphore>>critical:
TextCollector>>showCr:
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
Object: String error: Invalid argument 'b': must be a SmallInteger
SystemExceptions.WrongClass(Exception)>>signal
SystemExceptions.WrongClass class>>signalOn:mustBe:
SystemExceptions.WrongClass class>>signalOn:mustBe:
String class(Behavior)>>new:
String(Collection)>>copyEmpty:
String(ArrayedCollection)>>copyFrom:to:
WriteStream>>contents
String(Object)>>printString
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
Object: 3 error: did not understand #replaceFrom:to:with:startingAt:
MessageNotUnderstood(Exception)>>signal
SmallInteger(Object)>>doesNotUnderstand: #replaceFrom:to:with:startingAt:
String(ArrayedCollection)>>copyFrom:to:
WriteStream>>contents
String(Object)>>printString
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
This one includes the end of the stdout, to illustrate an odd doubling
of 'c':
'a'
'b'
'c''c'Object: nil error: did not understand #generality
MessageNotUnderstood(Exception)>>signal
UndefinedObject(Object)>>doesNotUnderstand: #generality
SmallInteger>>+
FileStream(FileDescriptor)>>write:from:to:
FileStream>>flush
FileStream(Stream)>>nextPutAllFlush:
TextCollector>>primNextPutAll:
[] in TextCollector>>showCr:
[] in Semaphore>>critical:
BlockClosure>>ensure:
Semaphore>>critical:
TextCollector>>showCr:
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
Object: String error: did not understand #copyEmpty:
MessageNotUnderstood(Exception)>>signal
String class(Object)>>doesNotUnderstand: #copyEmpty:
WriteStream>>growCollection
WriteStream>>nextPut:
String>>printOn:
String(Object)>>printString
String(Object)>>printNl
TerminationExperiment>>busyLoop
TerminationExperiment>>run
UndefinedObject>>executeStatements
etc. etc.
Tony
--
[][][] Tony Garnock-Jones | Mob: +44 (0)7905 974 211
[][] LShift Ltd | Tel: +44 (0)20 7729 7060
[] [] http://www.lshift.net/ | Email: address@hidden
Object subclass: TerminationExperiment [
busyLoop [
| ptr count |
count := 0.
[
'a' printNl.
'b' printNl.
'c' printNl.
count := count + 1.
(count \\ 100) = 0 ifTrue: [
Transcript << 'count: ' << count; nl.
Processor yield].
] repeat.
]
run [
| p |
p := Processor activeProcess.
p printNl.
[
Processor activeProcess printNl.
[
(Delay forMilliseconds: 1000) wait.
p terminate.
] repeat.
] fork.
self busyLoop.
]
run2 [
| p s |
s := Semaphore new.
p := [ [self busyLoop] ensure: [s signal] ] fork.
p printNl.
[
Processor activeProcess printNl.
[
(Delay forMilliseconds: 1000) wait.
p terminate.
] repeat.
] fork.
s wait.
]
].
TerminationExperiment new run.
"TerminationExperiment new run2."
- [Help-smalltalk] Random exceptions terminating root process,
Tony Garnock-Jones <=