Well, I did not consider the 64 bit.


Imho a perfect solution would be completely ageless and even work properly after the Big Crunch, but in this case I guess the present benchmark performance is more important :) Just committed the changes into the Inbox.


Best,

Christoph

________________________________
Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von tim Rowledge <tim at rowledge.org>
Gesendet: Mittwoch, 4. September 2019 21:09:26
An: The general-purpose Squeak developers list
Betreff: Re: [squeak-dev] The Inbox: ShoutCore-ct.71.mcz

Should point out here that #primUTCMicrosecondClock has been deprecated since 5.1 and replaced by Time class>>#utcMicrosecondClock.

And as for wrapping - well, a 64 bit value of microseconds starting at the beginning of 1901 will last quite a while. Call it a 63 bit value to stay positive, divide by 1e6, and 3600 and 24 and 365 and you get about 300,000 years in my workspace. I suspect that is far enough away to not be a practical issue. Or are we causing a Y302k problem?

> On 2019-09-04, at 11:51 AM, Thiede, Christoph <Christoph.Thiede at student.hpi.uni-potsdam.de> wrote:
>
> Hi Levente,
>
> thanks for the hint. I see #primUTCMicrosecondClock is more efficient, but do we really want to risk a clock wrap here (integer overflow)?
>
> Best,
> Christoph
>
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Levente Uzonyi <leves at caesar.elte.hu>
> Gesendet: Mittwoch, 4. September 2019 18:55:59
> An: squeak-dev at lists.squeakfoundation.org
> Betreff: Re: [squeak-dev] The Inbox: ShoutCore-ct.71.mcz
>
> Hi Christoph,
>
> On Tue, 3 Sep 2019, commits at source.squeak.org wrote:
>
> > A new version of ShoutCore was added to project The Inbox:
> > http://source.squeak.org/inbox/ShoutCore-ct.71.mcz
> >
> > ==================== Summary ====================
> >
> > Name: ShoutCore-ct.71
> > Author: ct
> > Time: 3 September 2019, 2:20:09.991948 pm
> > UUID: 2635dce1-6bda-3a4d-a726-3f66bb7c6431
> > Ancestors: ShoutCore-ul.68
> >
> > Use TimeStamps instead of deprecated #primUTCMicrosecondClock.
>
> In my understanding, TimeStamp is something we have been keeping around,
> because it's used for printing method timestamps, but for any other
> purpose there's its superclass: DateAndTime.
> With some effort, I think we could and should deprecate TimeStamp.
>
> #primUTCMicrosecondClock is still very useful, even though DateAndTime
> instances are not initialized with it anymore.
> For example, this primitive has the smallest overhead[1] to measure
> runtime with microsecond resolution, which is exactly what the method
> SHParserST80 class >> #benchmark uses it for.
>
> I mentioned it in an earlier mail that I intend to undeprecate it, and add
> the missing primitive 243 as well, which can be used to tell the VM to
> flush its time zone offset cache.
>
> Levente
>
> [1] It's a numbered primitive with no arguments returning an Integer. On
> 64-bits, that integer will stay a SmallInteger for quite a while, so
> there's no overhead on the image side to invoke it.
>
> >
> > =============== Diff against ShoutCore-ul.68 ===============
> >
> > Item was changed:
> >  ----- Method: SHParserST80 class>>benchmark (in category 'benchmarking') -----
> >  benchmark
> >
> >        | methods methodCount totalTime averageTime min median percentile80 percentile95 percentile99 max |
> >        Smalltalk garbageCollect.
> >        methods := OrderedCollection new: 100000.
> >        CurrentReadOnlySourceFiles cacheDuring: [
> >                | parser |
> >                parser := SHParserST80 new.
> >                SystemNavigation default allSelectorsAndMethodsDo: [ :class :selector :method |
> >                        | source start ranges |
> >                        source := method getSource asString.
> > +                      start := TimeStamp now.
> > -                      start := Time primUTCMicrosecondClock.
> >                        ranges := parser
> >                                rangesIn: source
> >                                classOrMetaClass: class
> >                                workspace: nil
> >                                environment: nil.
> > +                      methods addLast: { (TimeStamp now - start) asMicroSeconds. method. ranges size } ] ].
> > -                      methods addLast: { Time primUTCMicrosecondClock - start. method. ranges size } ] ].
> >        methods sort: #first asSortFunction.
> >        methodCount := methods size.
> >        totalTime := methods detectSum: #first.
> >        averageTime := (totalTime / methodCount) rounded.
> >
> >        min := methods first.
> >        median := methods at: methodCount // 2.
> >        percentile80 := methods at: (methodCount * 0.8) floor.
> >        percentile95 := methods at: (methodCount * 0.95) floor.
> >        percentile99 := methods at: (methodCount * 0.99) floor.
> >        max := methods last.
> >        ^'
> >        Methods         {1}
> >        Total                   {2}ms
> >        Average         {3}ms
> >        Min                             {4}ms {5} range(s) ({6})
> >        Median                  {7}ms {8} ranges ({9})
> >        80th percentile {10}ms {11} ranges ({12})
> >        95th percentile {13}ms {14} ranges ({15})
> >        99th percentile {16}ms {17} ranges ({18})
> >        Max                     {19}ms {20} ranges ({21})' format: ({
> >                methodCount asString.
> >                totalTime.
> >                averageTime.
> >                min first.
> >                min third asString.
> >                min second reference.
> >                median first.
> >                median third asString.
> >                median second reference.
> >                percentile80 first.
> >                percentile80 third asString.
> >                percentile80 second reference.
> >                percentile95 first.
> >                percentile95 third asString.
> >                percentile95 second reference.
> >                percentile99 first.
> >                percentile99 third asString.
> >                percentile99 second reference.
> >                max first.
> >                max third asString.
> >                max second reference } replace: [ :each |
> >                        each isNumber
> >                                ifTrue: [ (each / 1000) printShowingDecimalPlaces: 3 ]
> >                                ifFalse: [ each ] ])!


tim
--
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
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