PS it strikes me that using number of available stack pages is the right discriminator between Interpreter and all the cog VMs.  If we did get interpreter working with spur I'm sure we'd still have the full set of VM parameters, but more of them would be nil.

_,,,^..^,,,_ (phone)

> On Jan 29, 2016, at 10:52 AM, David T. Lewis <lewis at mail.msen.com> wrote:
> 
> Hi Eliot,
> 
> I ran into in testing the V3 update stream I have been maintaining on
> http://www.squeaksource.com/TrunkUpdateStreamV3. I think it's an
> interesting experiment for a number or reasons, although I have not been
> discussing it on the list because I don't want to invite confusion or
> distract attention from our main Spur/trunk work. But please indulge me in
> my occasional private experiments :-)
> 
> Dave
> 
>> Hi David,
>> 
>>    why bother?  Since the two never need to coexist doesn't it make sense
>> to have two different, simple, more readable versions?  I find the
>> code complex and since it is important, want to keep it as
>> comprehensible as possible.  I think in this case it is better to let
>> the two diverge.  You're just adding back cost we don't need to pay.
>> 
>> _,,,^..^,,,_ (phone)
>> 
>>> On Jan 29, 2016, at 7:31 AM, commits at source.squeak.org wrote:
>>> 
>>> David T. Lewis uploaded a new version of System to project The Trunk:
>>> http://source.squeak.org/trunk/System-dtl.790.mcz
>>> 
>>> ==================== Summary ====================
>>> 
>>> Name: System-dtl.790
>>> Author: dtl
>>> Time: 29 January 2016, 11:37:48.065507 pm
>>> UUID: 1ccde720-42a2-41fe-bcc4-cb9694d5af07
>>> Ancestors: System-eem.789
>>> 
>>> Update vmStatisticsReportString to restore memory stats when running on
>>> pre-spur VM.
>>> 
>>> =============== Diff against System-eem.789 ===============
>>> 
>>> Item was changed:
>>> ----- Method: SmalltalkImage>>vmStatisticsReportString (in category 'vm
>>> statistics') -----
>>> vmStatisticsReportString
>>>     "(Workspace new contents: Smalltalk vmStatisticsReportString)
>>>         openLabel: 'VM Statistics'"
>>>     "StringHolderView
>>>         open: (StringHolder new contents: Smalltalk
>>> vmStatisticsReportString)
>>>         label: 'VM Statistics'"
>>> 
>>>     | params oldSpaceEnd youngSpaceEnd memorySize fullGCs fullGCTime
>>> incrGCs incrGCTime tenureCount upTime upTime2 fullGCs2 fullGCTime2
>>> incrGCs2 incrGCTime2 tenureCount2 str freeSize youngSize used |
>>>     params := self getVMParameters.
>>>     oldSpaceEnd            := params at: 1.
>>>     youngSpaceEnd        := params at: 2.
>>>     memorySize            := params at: 3.
>>>     fullGCs                := params at: 7.
>>>     fullGCTime            := params at: 8.
>>>     incrGCs                := params at: 9.
>>>     incrGCTime            := params at: 10.
>>>     tenureCount            := params at: 11.
>>>     upTime := (params at: 20) ~= 0 "utcMicrosecondClock at startupp in
>>> later Spur VMs"
>>>                 ifTrue: [Time utcMicrosecondClock - (params at: 20) +
>>> 500 // 1000]
>>>                 ifFalse: [Time eventMillisecondClock]. "Fall back on
>>> old microsecond clock; Good for 47.5 days"
>>> 
>>>     str := WriteStream on: (String new: 700).
>>>     str    nextPutAll: 'uptime            ';
>>>         print: (upTime / 1000 / 60 // 60); nextPut: $h;
>>>         print: (upTime / 1000 / 60 \\ 60) asInteger; nextPut: $m;
>>>         print: (upTime / 1000 \\ 60) asInteger; nextPut: $s; cr.
>>> 
>>>     str    nextPutAll: 'memory        ';
>>>         nextPutAll: memorySize asStringWithCommas; nextPutAll: '
>>> bytes'; cr.
>>>     str    nextPutAll:    '    old            ';
>>>         nextPutAll: oldSpaceEnd asStringWithCommas; nextPutAll: ' bytes
>>> (';
>>>         print: (oldSpaceEnd / memorySize * 100) maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr.
>>> -    youngSize := params at: 44.
>>> -    str    nextPutAll: '    young        ';
>>> -        nextPutAll: youngSize asStringWithCommas; nextPutAll: ' bytes
>>> (';
>>> -        print: youngSize / memorySize * 100 maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr.
>>> -    youngSize := youngSpaceEnd. "used eden"
>>> -    freeSize := (params at: 54) + (params at: 44) - youngSize.
>>> -    used := youngSize + oldSpaceEnd - freeSize.
>>> -    str    nextPutAll: '    used        ';
>>> -        nextPutAll: used asStringWithCommas; nextPutAll: ' bytes (';
>>> -        print: used / memorySize * 100 maxDecimalPlaces: 1; nextPutAll:
>>> '%)'; cr.
>>> -    str    nextPutAll: '    free        ';
>>> -        nextPutAll: freeSize asStringWithCommas; nextPutAll: ' bytes
>>> (';
>>> -        print: freeSize / memorySize * 100 maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr.
>>> 
>>> +    params size >= 54 ifTrue: [ "Spur object memory"
>>> +        youngSize := params at: 44.
>>> +        str    nextPutAll: '    young        ';
>>> +            nextPutAll: youngSize asStringWithCommas; nextPutAll: '
>>> bytes (';
>>> +            print: youngSize / memorySize * 100 maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr.
>>> +        youngSize := youngSpaceEnd. "used eden"
>>> +        freeSize := (params at: 54) + (params at: 44) - youngSize.
>>> +        used := youngSize + oldSpaceEnd - freeSize.
>>> +        str    nextPutAll: '    used        ';
>>> +            nextPutAll: used asStringWithCommas; nextPutAll: ' bytes
>>> (';
>>> +            print: used / memorySize * 100 maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr.
>>> +        str    nextPutAll: '    free        ';
>>> +            nextPutAll: freeSize asStringWithCommas; nextPutAll: '
>>> bytes (';
>>> +            print: freeSize / memorySize * 100 maxDecimalPlaces: 1;
>>> nextPutAll: '%)'; cr
>>> +    ] ifFalse: [ "Earlier VM and V3 object memory"
>>> +        str    nextPutAll: '    young        ';
>>> +            nextPutAll: (youngSpaceEnd - oldSpaceEnd)
>>> asStringWithCommas; nextPutAll: ' bytes (';
>>> +            print: (youngSpaceEnd - oldSpaceEnd / memorySize * 100)
>>> maxDecimalPlaces: 1; nextPutAll: '%)'; cr.
>>> +        str    nextPutAll: '    used        ';
>>> +            nextPutAll: youngSpaceEnd asStringWithCommas; nextPutAll: '
>>> bytes (';
>>> +            print: (youngSpaceEnd / memoryEnd * 100) maxDecimalPlaces:
>>> 1; nextPutAll: '%)'; cr.
>>> +        str    nextPutAll: '    free        ';
>>> +            nextPutAll: (memoryEnd - youngSpaceEnd) asStringWithCommas;
>>> nextPutAll: ' bytes (';
>>> +            print: (memoryEnd - youngSpaceEnd / memoryEnd * 100)
>>> maxDecimalPlaces: 1; nextPutAll: '%)'; cr.
>>> +    ].
>>> +
>>>     str    nextPutAll: 'GCs            ';
>>>         nextPutAll: (fullGCs + incrGCs) asStringWithCommas.
>>>     fullGCs + incrGCs > 0 ifTrue: [
>>>         str
>>>             nextPutAll: ' (';
>>>             print: (upTime / (fullGCs + incrGCs)) maxDecimalPlaces: 1;
>>>             nextPutAll: ' ms between GCs)'
>>>     ].
>>>     str cr.
>>>     str    nextPutAll: '    full            ';
>>>         nextPutAll: fullGCs asStringWithCommas; nextPutAll: ' totalling
>>> '; nextPutAll: fullGCTime asStringWithCommas; nextPutAll: ' ms
>>> (';
>>>         print: (fullGCTime / upTime * 100) maxDecimalPlaces: 1;
>>>         nextPutAll: '% uptime)'.
>>>     fullGCs = 0 ifFalse:
>>>         [str    nextPutAll: ', avg '; print: (fullGCTime / fullGCs)
>>> maxDecimalPlaces: 1; nextPutAll: ' ms'].
>>>     str    cr.
>>>     str    nextPutAll: '    incr            ';
>>>         nextPutAll: incrGCs asStringWithCommas; nextPutAll: ' totalling
>>> '; nextPutAll: incrGCTime asStringWithCommas; nextPutAll: ' ms
>>> (';
>>>         print: (incrGCTime / upTime * 100) maxDecimalPlaces: 1;
>>>         nextPutAll: '% uptime), avg '; print: (incrGCTime / incrGCs)
>>> maxDecimalPlaces: 1; nextPutAll: ' ms'; cr.
>>>     str    nextPutAll: '    tenures        ';
>>>         nextPutAll: tenureCount asStringWithCommas.
>>>     tenureCount = 0 ifFalse:
>>>         [str nextPutAll: ' (avg '; print: incrGCs // tenureCount;
>>> nextPutAll: ' GCs/tenure)'].
>>>     str    cr.
>>> 
>>> LastStats ifNil: [LastStats := Array new: 6]
>>> ifNotNil: [
>>>     upTime2 := upTime - (LastStats at: 1).
>>>     fullGCs2 := fullGCs - (LastStats at: 2).
>>>     fullGCTime2 := fullGCTime - (LastStats at: 3).
>>>     incrGCs2 := incrGCs - (LastStats at: 4).
>>>     incrGCTime2 := incrGCTime - (LastStats at: 5).
>>>     tenureCount2 := tenureCount - (LastStats at: 6).
>>> 
>>>     str    nextPutAll: self textMarkerForShortReport ;
>>>         nextPutAll: (fullGCs2 + incrGCs2) asStringWithCommas.
>>>     fullGCs2 + incrGCs2 > 0 ifTrue: [
>>>         str
>>>             nextPutAll: ' (';
>>>             print: upTime2 // (fullGCs2 + incrGCs2);
>>>             nextPutAll: ' ms between GCs)'.
>>>     ].
>>>     str cr.
>>>     str    nextPutAll: '    uptime        '; print: (upTime2 / 1000.0)
>>> maxDecimalPlaces: 1; nextPutAll: ' s'; cr.
>>>     str    nextPutAll: '    full            ';
>>>         nextPutAll: fullGCs2 asStringWithCommas; nextPutAll: '
>>> totalling '; nextPutAll: fullGCTime2 asStringWithCommas;
>>> nextPutAll: ' ms (';
>>>         print: (fullGCTime2 / upTime2 * 100) maxDecimalPlaces: 1;
>>>         nextPutAll: '% uptime)'.
>>>     fullGCs2 = 0 ifFalse:
>>>         [str    nextPutAll: ', avg '; print: (fullGCTime2 / fullGCs2)
>>> maxDecimalPlaces: 1; nextPutAll: ' ms'].
>>>     str    cr.
>>>     str    nextPutAll: '    incr            ';
>>>         nextPutAll: incrGCs2 asStringWithCommas; nextPutAll: '
>>> totalling '; nextPutAll: incrGCTime2 asStringWithCommas;
>>> nextPutAll: ' ms (';
>>>         print: (incrGCTime2 / upTime2 * 100) maxDecimalPlaces: 1;
>>>         nextPutAll: '% uptime), avg '.
>>>     incrGCs2 > 0 ifTrue: [
>>>          str print: (incrGCTime2 / incrGCs2) maxDecimalPlaces: 1;
>>> nextPutAll: ' ms'
>>>     ].
>>>     str cr.
>>>     str    nextPutAll: '    tenures        ';
>>>         nextPutAll: tenureCount2 asStringWithCommas.
>>>     tenureCount2 = 0 ifFalse:
>>>         [str nextPutAll: ' (avg '; print: incrGCs2 // tenureCount2;
>>> nextPutAll: ' GCs/tenure)'].
>>>     str    cr.
>>> ].
>>>     LastStats at: 1 put: upTime.
>>>     LastStats at: 2 put: fullGCs.
>>>     LastStats at: 3 put: fullGCTime.
>>>     LastStats at: 4 put: incrGCs.
>>>     LastStats at: 5 put: incrGCTime.
>>>     LastStats at: 6 put: tenureCount.
>>> 
>>>     ^ str contents
>>> !
> 
> 
>