[Glass] Explanation to "too many failed pom_gen scavenges" in this context??
Mariano Martinez Peck via Glass
glass at lists.gemtalksystems.com
Tue Mar 8 10:57:28 PST 2016
On Tue, Mar 8, 2016 at 3:13 PM, Dale Henrichs <
dale.henrichs at gemtalksystems.com> wrote:
>
>
> On 03/08/2016 09:50 AM, Mariano Martinez Peck wrote:
>
> Hi guys,
>
> First of all, thanks to Richard for the suggestion. Adding the env var did
> write the useful info in the gem log.
>
> Problem is that even if I tried to fix it (in my code), I still failed :(
> I attach the whole log in case someone wants to take a look.
>
> However, I think there is something strange in
> #installAlmostOutOfMemoryStaticHandler:. I added some logging to this
> method to see what was going on (in bold the important parts):
>
>
> *installAlmostOutOfMemoryStaticHandler: initialCommitThreshold*
> * | handler commitThreshold used |*
> * commitThreshold := initialCommitThreshold.*
> * handler := AlmostOutOfMemory*
> * addDefaultHandler: [ :ex | *
> * "Exception caught, do a commit."*
> * Transcript*
> * show: 'exception handled: ' , ex printString;*
> * cr.*
> * System commitTransaction*
> * ifFalse: [ *
> * Transcript*
> * show: 'AutoCommit failed';*
> * cr.*
> * nil error: 'AutoCommit failed' ].*
> * System _vmMarkSweep.*
> * Transcript*
> * show: 'commit threshold value: ' , commitThreshold printString;*
> * cr.*
> * used := System _tempObjSpacePercentUsedLastMark.*
> * Transcript*
> * show: 'percent used ' , used printString;*
> * cr.*
> * used < commitThreshold*
> * ifTrue: [ *
> * "We dropped below the threshold, reenable the signal"*
> * Transcript*
> * show: 're-enable the signal ';*
> * cr.*
> * System enableAlmostOutOfMemoryError ]*
> * ifFalse: [ *
> * "commit and mark sweep did drop us below threshold. cut
> threshold in half *
> * and try again. Record an entry in the object log "*
> * commitThreshold := (100 - commitThreshold) // 2 +
> commitThreshold.*
> * Transcript*
> * show: 'commit threshold value: ' , commitThreshold
> printString;*
> * cr.*
> * commitThreshold < 98*
> * ifTrue: [ *
> * Transcript*
> * show: 'signalAlmostOutOfMemoryThreshold: ';*
> * cr.*
> * System signalAlmostOutOfMemoryThreshold: commitThreshold ]*
> * ifFalse: [ *
> * "we're with 10% of out of memory, commit instance counts
> structure *
> * into objectlog for posterity."*
> * Transcript*
> * show: '10% out of memory... record in the object log ';*
> * cr.*
> * (ObjectLogEntry*
> * trace: 'almost out of memory: ' , commitThreshold
> printString*
> * object: (System _vmInstanceCountsReport: 3)) addToLog.*
> * System commitTransaction*
> * ifFalse: [ *
> * Transcript*
> * show: 'Last AutoCommit failed ';*
> * cr.*
> * nil error: 'AutoCommit failed' ] ] ].*
> * ex resume ].*
> * SessionTemps current*
> * at: #'CommitOnAlmostOutOfMemoryStaticException'*
> * put: handler.*
> * System signalAlmostOutOfMemoryThreshold: commitThreshold*
>
>
>
> Now...if I check the gem log, I get this:
>
> *--transcript--'exception handled: a AlmostOutOfMemory occurred
> (notification 6013), Session''s temporary object memory is almost full'*
> *--transcript--'commit threshold value: 10'*
> *--transcript--'percent used 0'*
> *--transcript--'re-enable the signal '*
>
> And that 4 lines repeated several times, until it starts with the:
>
>
> ************ Fatal error 4067 OutOfMemory ******
>
> *Printing Smalltalk stack because of OutOfMemory:*
> *Smalltalk stack: printing to topaz .out file at [03/08/2016 12:36:11.827
> EST]*
>
>
>
> And this is what I don't understand...from the transcript, it seems that "*System
> _tempObjSpacePercentUsedLastMark" *always answered 0, hence we are below
> threshold (no problem!). But then I get the OutOfMemory anyway... so...
> how can I run out of memory if #_tempObjSpacePercentUsedLastMark answered 0
> each time?
>
>
> Okay the `--transcript--'re-enable the signal '` simply means that the
> AlmostOfMemory signal was re-enabled - the handler is armed - it does not
> guarantee that you won't run out of memory.
>
> The `*********** Fatal error 4067 OutOfMemory *****` means that you ran
> out of memory without triggering an AlmostOutOfMemory exception ... for the
> reasons I mentioned earlier: most likely you ran out of memory during a
> primitive call BEFORE the deferred exception could be signaled ..
>
>
OK, I got it, and that would explain it. OK.
> BTW, I tried looking at the selector in my 3.2.9 and didn't see symbols,
> so I don't know what methods are actually being called in the first couple
> of frames, so I can't guess about what might be consuming memory ...
>
>
OK.. I did some analysis. The most complicated part that I didn't know how
to debug was the "blocks" entries in the stack. Until some time I figured
out I could use:
(Object _objectForOop: XXX) _sourceStringForBlock
where XXX is the OOP of the GsNMethod printed at the END of the line, not
the homeMethod printing at the beginning.
This is the resulting, translated analysis. Please, start reading from the
bottom to the top.
Thanks!!
1 Object >> #'at:' (receiver is OrderedCollection)
2. The closure
'[ :coDataRowDict | coDataRowDict row at: index ]'
3. SequenceableCollection >> #'collect:'
4. Looks to me the closure of #mapSelectedRows: inputListOfRowDictionaries
toQuuveUsing: quuveKeysForZacksTableAccessor prependKeysWith: aPrefix ,
that is:
[ :rowDict |
| key tmp values dataType |
...
values := aListOfRowDictionaries collect: [ :coDataRowDict | coDataRowDict
row at: index ].
....
]
5. The closure of #doWithRowDictionaries: that is:
[ :row | | t|
t := self rowAsRowDictionary: row. "now the user can use symbolic
references for testing in the aTestBlock"
(aBlock value: t)
].
6. Collection >> do:
7. FaTableAccessor >> doWithRowDictionaries: aBlock
self table
do: [ :row |
| t |
t := self rowAsRowDictionary: row. "now the user can use symbolic
references for testing in the aTestBlock"
aBlock value: t ]
8 FaQuandlZacksFundamentalsDataLoader >> mapSelectedRows:
inputListOfRowDictionaries toQuuveUsing: quuveKeysForZacksTableAccessor
prependKeysWith: aPrefix
"some code here"
....
quuveKeysForZacksTableAccessor doWithRowDictionaries: [ :rowDict |
| key tmp values dataType |
...
values := aListOfRowDictionaries collect: [ :coDataRowDict | coDataRowDict
row at: index ].
....
]
--
Mariano
http://marianopeck.wordpress.com
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