On 20 April 2012 03:51, Levente Uzonyi <[email protected]> wrote: > On Thu, 19 Apr 2012, Frank Shearar wrote: > >> I found a serious bug in parsing numbers with negative exponents. It >> was completey broken, in fact, parsing 1e-1 as 10, not 1 / 10. Anyway. >> This version fixes that, and adds a bunch of tests demonstrating that >> number parsing will return rationals if it can. >> >> It's significantly slower than Squeak's SqNumberParser: >> >> Time millisecondsToRun: [100000 timesRepeat: [SqNumberParser parse: >> '1234567890']] => 466 >> >> Time millisecondsToRun: [100000 timesRepeat: [PPSmalltalkNumberParser >> parse: '1234567890']] => 32082 >> >> I've attached a MessageTally spying on the latter: I've not much skill >> in reading these, but nothing leaps out at me as being obviously >> awful. > > > Didn't check the code, just the tally, and I think that > PPSmalltalkNumberParser(PPSmalltalkNumberGrammar)>>digitsBase: is begging > for optimization. It's probably also the cause of the high amount of garbage > which causes significant amount of time spent with garbage collection. > It's also interesting is that the finalization process does so much work, > there may be something wrong with your image.
Thanks for taking a look, Levente. I'd expect digitsBase: to dominate the running costs, given that we're parsing numbers. I do make a large number of throwaway "immutable" values with a Builder-like pattern... in PPSmalltalkNumberParser >> #makeNumberFrom:base:. That, I would imagine, could explain the garbage? If I may, what do you look for when reading the MessageTally? How do you tell, for instance, that there's excessive garbage production? That the incremental GCs take 7ms? (I'm reading Andreas' comments on http://wiki.squeak.org/squeak/4210 again.) frank > Levente > > >> >> frank >> >> On 14 September 2011 20:26, Frank Shearar <[email protected]> wrote: >>> >>> On 3 September 2011 19:35, Nicolas Cellier >>> <[email protected]> wrote: >>>> >>>> 2011/9/3 Frank Shearar <[email protected]>: >>>>> >>>>> On 3 September 2011 18:50, Lukas Renggli <[email protected]> wrote: >>>>>> >>>>>> I think it is a good idea to have the number parser separate, after >>>>>> all it might also make sense to use it separately. >>>>>> >>>>>> It seems that the new Smalltalk grammar is significantly slower. The >>>>>> benchmark PPSmalltalkClassesTests class>>#benchmark: that uses the >>>>>> source code of the collection hierarchy and does not especially target >>>>>> number literals runs 30% slower. >>>>>> >>>>>> Also I see that "Number readFrom: ..." is still used within the >>>>>> grammar. This seems to be a bit strange, no? >>>>> >>>>> >>>>> Yes: it's a double-parse, which is a bit lame. First, we parse the >>>>> literal with PPSmalltalkNumberParser, which ensures that the thing >>>>> given to Number class >> #readFrom: is a well-formed token (so, in >>>>> particular, Squeak's Number doesn't get to see anything other than a >>>>> well-formed token). >>>>> >>>>> It sounds like you're happy with the basic concept, so maybe I should >>>>> remove the Number class >> #readFrom: stuff, see if I can't remove the >>>>> performance issues, and resubmit the patch. >>>>> >>>>> frank >>>>> >>>> >>>> Yes, a NumberParser is essentially parsing, and this duplication sounds >>>> useless. >>>> The main feature of interest in NumberParser that I consider a >>>> requirement and should find its equivalence in a PetitNumberParser is: >>>> - round a decimal representation to nearest Float >>>> It's simple, just convert a Fraction asFloat in a single final step to >>>> avoid cumulating round off errors - see >>>> #makeFloatFromMantissa:exponent:base: >>>> >>>> The second feature of interest in NumberParser is the ability to >>>> parser LargeInteger efficiently by avoiding (10 * largeValue + >>>> digitValue) loops, and replacing them with a log(n) cost. >>>> This would be a simple thing to implement in a functional language. >>> >>> >>> Hopefully this won't offend your sensibilities too much :). It does, >>> in fact, use 10* loops - I wrote an experimental "front half * rear >>> half" recursion, which was slower in my benchmarks. >>> >>> This version has the grammar and parser doing no string->number >>> conversion at all. PPSmalltalkNumberMaker supplies a number of utility >>> methods designed to stop one from making malformed numbers. It also >>> supplies a builder interface that the parser uses to construct >>> numbers. >>> >>> frank >>> >>>> Nicolas >>>> >>>>>> Lukas >>>>>> >>>>>> >>>>>> On 3 September 2011 17:18, Frank Shearar <[email protected]> >>>>>> wrote: >>>>>>> >>>>>>> On 3 September 2011 15:56, Lukas Renggli <[email protected]> wrote: >>>>>>>> >>>>>>>> On 3 September 2011 16:51, Frank Shearar <[email protected]> >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> Hi Lukas, >>>>>>>>> >>>>>>>>> I haven't :) mainly because I'm unsure where to put it - is there >>>>>>>>> perhaps a PP Inbox, or shall I just post the merged version, or >>>>>>>>> what's >>>>>>>>> your preference? (How about an mcd between my merge and PP's head?) >>>>>>>> >>>>>>>> >>>>>>>> Just put the .mcz at some public URL (dropbox, squeak source, ...) >>>>>>>> or >>>>>>>> attach it to a mail. >>>>>>> >>>>>>> >>>>>>> Ah, great - here it is. You'll see I've written the grammar as a >>>>>>> separate class. That was really more to make what I'd done more >>>>>>> obvious and to minimise the change to PPSmalltalkGrammar, but perhaps >>>>>>> it's not a bad idea anyway: it's easy to see the number literal >>>>>>> subgrammar. >>>>>>> >>>>>>> frank >>>>>>> >>>>>>>> Lukas >>>>>>>> >>>>>>>> -- >>>>>>>> Lukas Renggli >>>>>>>> www.lukas-renggli.ch >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Lukas Renggli >>>>>> www.lukas-renggli.ch >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >> >
