[squeak-dev] The Inbox: Chronology-Core-cmm.56.mczLevente Uzonyi leves at caesar.elte.huTue May 5 01:17:00 UTC 2020
Hi Chris, On Mon, 4 May 2020, Chris Muller wrote: > Hi Levente, > This trades the "posix" nomenclature in the API for #microsecondClockValue. "Posix" is a private matter to Chronology's implementation that should not be exposed in the API. "Posix" has been there since 2016: Time class >> posixMicrosecondClockWithOffset:. Everyone gets an idea what kind of timestamp a method with posix in its name will return. The same does not apply to #microsecondClockValue, does it? In my opinion exposing "Posix" has benefits. So, -1 to these changes. Details below. > > - Chris > > > On Mon, May 4, 2020 at 6:42 PM <commits at source.squeak.org> wrote: > Chris Muller uploaded a new version of Chronology-Core to project The Inbox: > http://source.squeak.org/inbox/Chronology-Core-cmm.56.mcz > > ==================== Summary ==================== > > Name: Chronology-Core-cmm.56 > Author: cmm > Time: 4 May 2020, 6:42:27.516151 pm > UUID: 3c97bedc-c192-4872-b0f2-e93199f506ce > Ancestors: Chronology-Core-ul.54 > > Building on Chronology-Core-ul.54: > > - Let #microsecondClockValue complement #millisecondClockValue, to offer higher precision. > - New constructor, DateAndTime class>>#utcMicroseconds:, complements the above. > - Make Time class>>#utcMicrosecondClock private to help avoid accidental improper use with the above. > > =============== Diff against Chronology-Core-ul.54 =============== > > Item was added: > + ----- Method: DateAndTime class>>microsecondClockValue (in category 'smalltalk-80') ----- > + microsecondClockValue > + ^ self clock microsecondClockValue! Why do we need this here? Especially in that category. This is clearly not part of any smalltalk-80 protocol. DateAndTime class >> ##millisecondClockValue has no senders, so we should remove that method instead of adding another unused one. > > Item was added: > + ----- Method: DateAndTime class>>utcMicroseconds: (in category 'instance creation') ----- > + utcMicroseconds: microsecondClockValue > + "Instantiate a DateAndTime in UTC from the value of my #microsecondClockValue." > + ^ super new > + utcMicroseconds: microsecondClockValue > + offset: 0! > > Item was changed: > ----- Method: Time class>>estimateHighResClockTicksPerMillisecond (in category 'clock') ----- > estimateHighResClockTicksPerMillisecond > > | t0 t1 t2 t3 | > > "Count the ticks ellapsed during a 10ms busy loop" > + t0 := Time microsecondClockValue + 200. > + [Time microsecondClockValue >= t0] whileFalse. > - t0 := Time utcMicrosecondClock + 200. > - [Time utcMicrosecondClock >= t0] whileFalse. > t1 := self highResClock. > + [Time microsecondClockValue >= (t0 + 10000)] whileFalse. > + t1 := self highResClock - t1 * 1000 // (Time microsecondClockValue - t0). > - [Time utcMicrosecondClock >= (t0 + 10000)] whileFalse. > - t1 := self highResClock - t1 * 1000 // (Time utcMicrosecondClock - t0). The method uses the primitive directly to make the measurements as accurate as possible. This change would make them less accurate. > > "Count the ticks ellapsed during a 20ms busy loop" > + t0 := Time microsecondClockValue + 200. > + [Time microsecondClockValue >= t0] whileFalse. > - t0 := Time utcMicrosecondClock + 200. > - [Time utcMicrosecondClock >= t0] whileFalse. > t2 := self highResClock. > + [Time microsecondClockValue >= (t0 + 20000)] whileFalse. > + t2 := self highResClock - t2 * 1000 // (Time microsecondClockValue - t0). > - [Time utcMicrosecondClock >= (t0 + 20000)] whileFalse. > - t2 := self highResClock - t2 * 1000 // (Time utcMicrosecondClock - t0). > > "Count the ticks ellapsed during a 30ms busy loop" > + t0 := Time microsecondClockValue + 200. > + [Time microsecondClockValue >= t0] whileFalse. > - t0 := Time utcMicrosecondClock + 200. > - [Time utcMicrosecondClock >= t0] whileFalse. > t3 := self highResClock. > + [Time microsecondClockValue >= (t0 + 30000)] whileFalse. > + t3 := self highResClock - t3 * 1000 // (Time microsecondClockValue - t0). > - [Time utcMicrosecondClock >= (t0 + 30000)] whileFalse. > - t3 := self highResClock - t3 * 1000 // (Time utcMicrosecondClock - t0). > > "Take the median of the 3 estimates as the best" > ^ t1 <= t2 > ifTrue: [t2 <= t3 > ifTrue: [t2] > ifFalse: [t1 <= t3 > ifTrue: [t3] > ifFalse: [t1]]] > ifFalse: [t1 <= t3 > ifTrue: [t1] > ifFalse: [t2 <= t3 > ifTrue: [t3] > ifFalse: [t2]]]! > > Item was added: > + ----- Method: Time class>>microsecondClockValue (in category 'general inquiries') ----- > + microsecondClockValue > + "Answer the value of the microsecond clock, the number of microseconds elapsed since 1/1/1901 @ 00:00:00." Wrong date there. > + ^ self utcMicrosecondClock - MicrosecondsBetweenPosixEpochAndSqueakEpoch! > > Item was changed: > ----- Method: Time class>>microsecondsToRun: (in category 'general inquiries') ----- > microsecondsToRun: timedBlock > "Answer the number of microseconds timedBlock takes to return its value." > > | startUsecs | > (self useHighResClockForTiming and: [self highResClock ~= 0]) > ifTrue: [ ^(self nanosecondsToRunHighRes: timedBlock) + 500 // 1000]. > + startUsecs := self microsecondClockValue. > - startUsecs := self utcMicrosecondClock. > timedBlock value. > + ^self microsecondClockValue - startUsecs! > - ^self utcMicrosecondClock - startUsecs! Again, decreases the measurement's accuracy. > > Item was changed: > ----- Method: Time class>>millisecondClockValue (in category 'general inquiries') ----- > millisecondClockValue > "Answer the value of the millisecond clock." > + ^self microsecondClockValue // 1000! > - > - ^self utcMicrosecondClock // 1000! After loading, this change would break code relying on previous results of this method. > > Item was changed: > ----- Method: Time class>>nanosecondsToRun: (in category 'general inquiries') ----- > nanosecondsToRun: timedBlock > "Answer the number of nanoseconds timedBlock takes to return its value. > Use high resolution clock if available and preferred." > > | startUsecs | > (self useHighResClockForTiming and: [self highResClock ~= 0]) > ifTrue: [ ^(self nanosecondsToRunHighRes: timedBlock)]. > "Fallback to microseconds clock" > + startUsecs := self microsecondClockValue. > - startUsecs := self utcMicrosecondClock. > timedBlock value. > + ^self microsecondClockValue - startUsecs * 1000! > - ^self utcMicrosecondClock - startUsecs * 1000! Accuracy again. > > Item was removed: > - ----- Method: Time class>>posixUtcMicrosecondClock (in category 'clock') ----- > - posixUtcMicrosecondClock > - "Answer the UTC microseconds since the POSIX epoch (January 1st 1970 00:00:00 UTC)." > - > - ^self utcMicrosecondClock - MicrosecondsBetweenPosixEpochAndSqueakEpoch! > > Item was changed: > + ----- Method: Time class>>utcMicrosecondClock (in category 'private') ----- > - ----- Method: Time class>>utcMicrosecondClock (in category 'clock') ----- Does this mean that I have to reimplement the primitive in my external packages from now on? Levente > utcMicrosecondClock > "Answer the UTC microseconds since the Smalltalk epoch (January 1st 1901, the start of the 20th century). > The value is derived from the Posix epoch with a constant offset corresponding to elapsed microseconds > between the two epochs according to RFC 868." > <primitive: 240> > ^0! > > > >
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