On Wed, Nov 2, 2011 at 11:33 AM, Levente Uzonyi leves@elte.hu wrote:
On Wed, 2 Nov 2011, Igor Stasenko wrote:
Here the original implementation, which Array inherits from
SequenceableCollection:
at: index ifAbsent: exceptionBlock "Answer the element at my position index. If I do not contain an element at index, answer the result of evaluating the argument, exceptionBlock."
(index between: 1 and: self size) ifTrue: [^ self at: index]. ^ exceptionBlock valuethe thing is, that #at: primivite also doing a range checking and fails if index is invalid, so if index is valid, as result we performing a range checking twice instead of just once.
Here the simple implementation how to make things faster: fat: index "Primitive. Assumes receiver is indexable. Answer the value of an indexable element in the receiver. Fail if the argument index is not an Integer or is out of bounds. Essential. See Object documentation whatIsAPrimitive. Read the class comment for a discussion about that the fact that the index can be a float."
<primitive: 60> ^ #ploppfat: index ifAbsent: aBlock | x | x := (self fat: index). x == #plopp ifTrue: [ ^ aBlock value ]. ^ x
And speedup is almost 2 times:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ] timeToRun
39
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ] timeToRun
20
Even when index is out of range, it is still much faster:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 100 ifAbsent: nil ] ] timeToRun
35
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) fat: 100 ifAbsent: nil ] ] timeToRun
24
The problem, of course, that trick with #plopp is a dirty hack. Because if array include an #plopp object as element, it will report as it absent, instead of answering it. There is no way to ensure that any arbitrary object are never included as element in array, so this is no-go for generic replacement. But in controlled environment, when you know that none of arrays which you using with #fat:ifAbsent: will ever include #plopp (or pick your own unique object) it may be a good alternative.
I've been thinking about this earlier and there's a much nicer and simpler solution, though it requires vm changes :). The idea is to change primitive 60 to work for 2 parameters too, so #at:ifAbsent: could also use the primitive directly. There were a few changes about #at: recently (mirror prims, cog), so I'm not sure it's still easy to change the primitive.
his is neat, but it wouldn't be an extension to primitive 60 but a new primitive that would ignore its top of stack. primitive 60 can operate with 2 args,when used as a mirror primitive, but then it ignores the receiver. Your usage would ignore the last argument.
So choose a primitive number and I'll make it so...
Levente
-- Best regards, Igor Stasenko.
On 2 November 2011 20:55, Eliot Miranda eliot.miranda@gmail.com wrote:
On Wed, Nov 2, 2011 at 11:33 AM, Levente Uzonyi leves@elte.hu wrote:
On Wed, 2 Nov 2011, Igor Stasenko wrote:
Here the original implementation, which Array inherits from SequenceableCollection:
at: index ifAbsent: exceptionBlock "Answer the element at my position index. If I do not contain an element at index, answer the result of evaluating the argument, exceptionBlock."
(index between: 1 and: self size) ifTrue: [^ self at: index]. ^ exceptionBlock value
the thing is, that #at: primivite also doing a range checking and fails if index is invalid, so if index is valid, as result we performing a range checking twice instead of just once.
Here the simple implementation how to make things faster: fat: index "Primitive. Assumes receiver is indexable. Answer the value of an indexable element in the receiver. Fail if the argument index is not an Integer or is out of bounds. Essential. See Object documentation whatIsAPrimitive. Read the class comment for a discussion about that the fact that the index can be a float."
<primitive: 60> ^ #plopp
fat: index ifAbsent: aBlock | x | x := (self fat: index). x == #plopp ifTrue: [ ^ aBlock value ]. ^ x
And speedup is almost 2 times:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ] timeToRun
39
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ] timeToRun
20
Even when index is out of range, it is still much faster:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 100 ifAbsent: nil ] ] timeToRun
35
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) fat: 100 ifAbsent: nil ] ] timeToRun
24
The problem, of course, that trick with #plopp is a dirty hack. Because if array include an #plopp object as element, it will report as it absent, instead of answering it. There is no way to ensure that any arbitrary object are never included as element in array, so this is no-go for generic replacement. But in controlled environment, when you know that none of arrays which you using with #fat:ifAbsent: will ever include #plopp (or pick your own unique object) it may be a good alternative.
I've been thinking about this earlier and there's a much nicer and simpler solution, though it requires vm changes :). The idea is to change primitive 60 to work for 2 parameters too, so #at:ifAbsent: could also use the primitive directly. There were a few changes about #at: recently (mirror prims, cog), so I'm not sure it's still easy to change the primitive.
his is neat, but it wouldn't be an extension to primitive 60 but a new primitive that would ignore its top of stack. primitive 60 can operate with 2 args,when used as a mirror primitive, but then it ignores the receiver. Your usage would ignore the last argument. So choose a primitive number and I'll make it so...
Of course i was thinking about changing VM too. But i am uncertain if it worth doing so, because maybe this is too low reward for putting effort in it.
But if we going to make new prim , here's what i'd like to have - use proper prim error code(s) to distinguish between cases: - a receiver is not indexable/variable object - an index is integer, but points outside of array's range - an object passed as index is non-integer
this is to eliminate code which tries to guess what is really happen:
<primitive: 60> index isInteger ifTrue: [self class isVariable ifTrue: [self errorSubscriptBounds: index] ifFalse: [self errorNotIndexable]]. index isNumber ifTrue: [^self at: index asInteger] ifFalse: [self errorNonIntegerIndex]
Btw, this is an example of how much more flexibility we could earn, if we could rewrite basic prims to count (and use) arguments from bottom of stack (receiver) instead from top, so primitives could be used in more flexible manner.
On Wed, Nov 2, 2011 at 1:15 PM, Igor Stasenko siguctua@gmail.com wrote:
On 2 November 2011 20:55, Eliot Miranda eliot.miranda@gmail.com wrote:
On Wed, Nov 2, 2011 at 11:33 AM, Levente Uzonyi leves@elte.hu wrote:
On Wed, 2 Nov 2011, Igor Stasenko wrote:
Here the original implementation, which Array inherits from SequenceableCollection:
at: index ifAbsent: exceptionBlock "Answer the element at my position index. If I do not contain
an element
at index, answer the result of evaluating the argument,exceptionBlock."
(index between: 1 and: self size) ifTrue: [^ self at: index]. ^ exceptionBlock valuethe thing is, that #at: primivite also doing a range checking and fails if index is invalid, so if index is valid, as result we performing a range checking twice instead of just once.
Here the simple implementation how to make things faster: fat: index "Primitive. Assumes receiver is indexable. Answer the value of
an
indexable element in the receiver. Fail if the argument indexis not an
Integer or is out of bounds. Essential. See Object documentation whatIsAPrimitive. Read the class comment for a discussion aboutthat the fact
that the index can be a float." <primitive: 60> ^ #ploppfat: index ifAbsent: aBlock | x | x := (self fat: index). x == #plopp ifTrue: [ ^ aBlock value ]. ^ x
And speedup is almost 2 times:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ]
timeToRun
39
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 1 ifAbsent: nil ] ]
timeToRun
20
Even when index is out of range, it is still much faster:
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) at: 100 ifAbsent: nil ] ]
timeToRun
35
[ 1000000 timesRepeat: [ #(1 2 4 5 56 67 67) fat: 100 ifAbsent: nil ] ] timeToRun
24
The problem, of course, that trick with #plopp is a dirty hack. Because if array include an #plopp object as element, it will report as it absent, instead of answering it. There is no way to ensure that any arbitrary object are never included as element in array, so this is no-go for generic replacement. But in controlled environment, when you know that none of arrays which you using with #fat:ifAbsent: will ever include #plopp (or pick your own unique object) it may be a good alternative.
I've been thinking about this earlier and there's a much nicer and
simpler solution, though it requires vm changes :). The idea is to change primitive 60 to work for 2 parameters too, so #at:ifAbsent: could also use the primitive directly. There were a few changes about #at: recently (mirror prims, cog), so I'm not sure it's still easy to change the primitive.
his is neat, but it wouldn't be an extension to primitive 60 but a new
primitive that would ignore its top of stack. primitive 60 can operate with 2 args,when used as a mirror primitive, but then it ignores the receiver. Your usage would ignore the last argument.
So choose a primitive number and I'll make it so...
Of course i was thinking about changing VM too. But i am uncertain if it worth doing so, because maybe this is too low reward for putting effort in it.
But if we going to make new prim , here's what i'd like to have
- use proper prim error code(s) to distinguish between cases:
- a receiver is not indexable/variable object
- an index is integer, but points outside of array's range
- an object passed as index is non-integer
I agree. I was going to brag that the Cog VM already has this implemented but the error code returned for a non-indexable receiver is wrong. It should be #'bad receiver' but the prim always answers #'bad index'. I'll fix this. Primitive error codes and relevant usage in primitives still need to be ported to the standard VM though.
this is to eliminate code which tries to guess what is really happen:
<primitive: 60> index isInteger ifTrue: [self class isVariable ifTrue: [self errorSubscriptBounds: index] ifFalse: [self errorNotIndexable]]. index isNumber ifTrue: [^self at: index asInteger] ifFalse: [self errorNonIntegerIndex]
Btw, this is an example of how much more flexibility we could earn, if we could rewrite basic prims to count (and use) arguments from bottom of stack (receiver) instead from top, so primitives could be used in more flexible manner.
-- Best regards, Igor Stasenko.
On Wed, Nov 02, 2011 at 01:23:33PM -0700, Eliot Miranda wrote:
On Wed, Nov 2, 2011 at 1:15 PM, Igor Stasenko siguctua@gmail.com wrote:
Of course i was thinking about changing VM too. But i am uncertain if it worth doing so, because maybe this is too low reward for putting effort in it.
But if we going to make new prim , here's what i'd like to have
- use proper prim error code(s) to distinguish between cases:
- a receiver is not indexable/variable object
- an index is integer, but points outside of array's range
- an object passed as index is non-integer
I agree. I was going to brag that the Cog VM already has this implemented but the error code returned for a non-indexable receiver is wrong. It should be #'bad receiver' but the prim always answers #'bad index'. I'll fix this. Primitive error codes and relevant usage in primitives still need to be ported to the standard VM though.
Hopefully we're not too far apart on this. I added your basic mechanism for error codes a while back (see below) so adding the relevant usage to primitives should be strightforward, and in principle a new primitive that uses error codes should work on both Cog and the standard VM.
Dave
Name: VMMaker-dtl.237 Author: dtl Time: 23 May 2011, 11:38:51.478 pm UUID: db716650-3b1b-4d54-9aba-6257a21a50a7 Ancestors: VMMaker-dtl.236
VMMaker 4.5.1
Convert primitive error reporting to use #primitiveFailFor: such that the successFlag variable is replaced with primFailCode (integer value, 0 for success, 1, 2, 3... for failure codes), consistent with oscog.
Includes improved #failed, #successful, and #success: methods recoded for performance in C, yielding performance equivalent to previous implementation with successFlag.
Changes were applied as follows:
- Replaced all occurances of "successFlag := true" with "self initPrimCall", which initialize primFailCode to 0. - Replaced all "successFlag := false" with "self primitiveFail". - Replaced all "successFlag ifTrue: [] ifFalse: []" with "self successful ifTrue: [] ifFalse: []". - Updated #primitiveFail, #failed and #success: to use primFailCode rather than successFlag. - Removed successFlag variable.
Elliot
How could we help there.
I would really like to sit with igor and do some stupid work on the VM. The best way to learn is to do something besides a master. So if this would be to help in addition I would really allocate time on my wonderfully exciting admin tasks granted by my status :)
I agree. I was going to brag that the Cog VM already has this implemented but the error code returned for a non-indexable receiver is wrong. It should be #'bad receiver' but the prim always answers #'bad index'. I'll fix this. Primitive error codes and relevant usage in primitives still need to be ported to the standard VM though.
Stef
vm-dev@lists.squeakfoundation.org
-
David T. Lewis -
Eliot Miranda -
Igor Stasenko -
stephane ducasse