Gambit-list Avril 2013

gambit-list@iro.umontreal.ca

21 participants
51 discussions

Efficient Compilation of Tail Calls and Continuations to JavaScript
by Marc Feeley 17 Sep '13

17 Sep '13

Eric Thivierge is in Copenhagen today, at the Scheme Workshop, presenting our latest paper: "Efficient Compilation of Tail Calls and Continuations to JavaScript" You can get the paper on the Scheme Worshop web page: http://users-cs.au.dk/danvy/sfp12/programme-sfp12.html It describes the implementation of tail calls and continuations in Gambit-JS and evaluates its performance. Even if you are not specifically interested in the JavaScript back-end the paper may be interesting to read as it provides a brief explanation of the Gambit Virtual Machine (GVM) and compiler front-end, and a complete example of compilation from Scheme, to GVM, to JavaScript. The performance evaluation (see attached tables) shows that the approach used by Gambit-JS is consistently faster than Scheme2JS and Spock. Marc Execution times using V8 (Chrome 21.0.1180.89): Gambit-JS Scheme2JS Spock fib35 .80 1.54 1.9x 2.40 3.0x nqueens12 .72 .76 1.1x 2.33 3.3x oddeven .83 1.92 2.3x 5.62 6.8x ctak .18 17.64 95.9x .59 3.2x contfib30 1.17 106.01 90.9x 3.38 2.9x btsearch2000 1.35 25.40 18.8x 7.93 5.9x threads10 1.34 24.68 18.5x 4.40 3.3x Execution times using JagerMonkey (Firefox 15.0.1): Gambit-JS Scheme2JS Spock fib35 1.07 7.66 7.2x 20.73 19.4x nqueens12 1.49 2.62 1.8x 12.97 8.7x oddeven 1.09 1.93 1.8x 33.91 31.1x ctak 1.25 30.38 24.3x 1.86 1.5x contfib30 5.88 156.79 26.7x 10.61 1.8x btsearch2000 11.19 27.16 2.4x 16.54 1.5x threads10 6.97 34.36 4.9x 22.11 3.2x Execution times using Nitro (Safari 6.0): Gambit-JS Scheme2JS Spock fib35 1.32 6.53 4.9x 84.69 64.2x nqueens12 1.31 1.89 1.4x 45.15 34.4x oddeven 2.52 1.55 .6x 143.97 57.1x ctak .30 52.88 177.4x 4.18 14.0x contfib30 1.60 2311.69 1443.0x 25.98 16.2x btsearch2000 3.46 102.98 29.7x 92.02 26.6x threads10 3.03 74.21 24.5x 74.88 24.7x

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Github issue tracking
by Marc Feeley 02 Mai '13

02 Mai '13

Hello. I've done a "git merging" blitz this morning to integrate the patches that were submitted on Gambit's github issue tracker (https://github.com/feeley/gambit/issues). I'd like to thank Michel Alexandre Salim, Francis Filion, Pierre-Luc Morneau-Lépine, Joseph Wayne Norton, and Dimitris Vyzovitis for their contributions. I'm getting to like the interface of the github issue tracker which I use for other projects as well, so please use it to post any issues you find with Gambit. It you want to contribute a patch, you can submit a pull request using the issue tracker. Marc

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Evaluation in reader?
by Nathan Sorenson 02 Mai '13

02 Mai '13

I'm the author of the Clojure->Scheme compiler. I'm looking into the possibility making the compiler not require the JVM for macro-expansion. Clojure makes use of vectors and maps directly as syntax -- I was looking into using Gambit's bracket-keyword to produce literal vectors from the reader, but it seems the reader just attaches a symbol to the head of a list, as opposed to evaluating the forms. I'd like the macro-expansion stage to have access to the actual maps, vectors etc. as some Clojure macros behave differently depending on whether the forms are lists or vectors. Is it possible to hook into the reader this way? (Perhaps as a fallback I could just tree-walk the forms to replace instances of the vector-literal and hash-literal markers with actual vectors and maps before macro-expansion.)

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Is it possible to build only libgambc?
by Ralph Möritz 02 Mai '13

02 Mai '13

Is it possible to build only certain parts of Gambit, eg. libgambc? The reason I ask is that I'm following Sean Chapel's Android example project on GitHub [1] and have to run `make' which breaks, but only after building libgambc, which is all I need. Happy coincidence. If the build order ever changes this fragile solution will stop working, so it would be nice to be able to specify libgambc as the `make' target ie. `make libgambc' or similar. Also, Sean's example doesn't first do a `make bootstrap' and `make bootclean' to remove stale .c files. Not sure if this would be possible anyway since `./configure' would have to be run again after `make bootclean' with `--host=arm-linux-eabi'. Anyone?

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Can't build 4.6.8 from src with c++ support
by Victor Boon 30 Avr '13

30 Avr '13

Hi I'm not able to build Gambit with C++ support, having problem with 4.6.7 and 4.6.8. Building on ubuntu 32bit. Full log is attached but here are the relevant parts: gcc 4.7.2 Both configure commands produce same error: ./configure --enable-single-host --enable-cplusplus --enable-c-opt ./configure --enable-single-host --enable-cplusplus g++ -Wno-unused -Wno-write-strings -O2 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fomit-frame-pointer -fPIC -fno-common -mieee-fp -I"../include" -c -o "os_io.o" -I. -DHAVE_CONFIG_H -D___GAMBCDIR="\"/usr/local/Gambit-C\"" -D___SYS_TYPE_CPU="\"i686\"" -D___SYS_TYPE_VENDOR="\"pc\"" -D___SYS_TYPE_OS="\"linux-gnu\"" -D___CONFIGURE_COMMAND="\"./configure '--enable-single-host' '--enable-c-opt' '--enable-cplusplus'"\" -D___OBJ_EXTENSION="\".o\"" -D___EXE_EXTENSION="\"\"" -D___BAT_EXTENSION="\"\"" -D___PRIMAL os_io.c -D___LIBRARY In file included from os_base.h:8:0, from os_io.c:14: os.h:1113:0: warning: "__USE_LARGEFILE64" redefined [enabled by default] In file included from /usr/include/limits.h:27:0, from /usr/lib/gcc/i686-linux-gnu/4.7/include-fixed/limits.h:169, from /usr/lib/gcc/i686-linux-gnu/4.7/include-fixed/syslimits.h:7, from /usr/lib/gcc/i686-linux-gnu/4.7/include-fixed/limits.h:34, from ../include/gambit.h:473, from os_io.c:12: /usr/include/features.h:281:0: note: this is the location of the previous definition os_io.c: In function ‘int ___device_select(___device**, int, int, ___time)’: os_io.c:1089:62: error: ‘___absolute_time_to_nonnegative_timeval’ was not declared in this scope os_io.c: In function ‘int ___device_stream_setup_from_process(___device_stream**, ___device_group*, char**, char**, char*, int)’: os_io.c:7201:77: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’, declared with attribute warn_unused_result [-Wunused-result] make[1]: *** [os_io.o] Error 1

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Promises & lazy thunks
by Jason Felice 30 Avr '13

30 Avr '13

Promises as specified in the Scheme spec are not terribly useful... but I was thinking that I could make a much cleaner implementation of lazy sequences and other things given a Scheme runtime which automatically forced promises when the promise is operated on as a value. I was wondering if anyone's thought about doing this. Also, if it's really as hard as making every primitive (except, course, promise?, promise-forced? and friends) check and force every parameter, or if there are any neat implementation tricks, especially if there's something which can be used in gambit (like error-handler, but that seems gross. Also, incomplete and messy). -Jason

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Simple benchmark of |->integer| and |->flonum| on integer, flonum and rational input. For the further if you have any idea of a definition faster than (inexact->exact (floor n)) feel free to share :)
by Mikael 30 Avr '13

30 Avr '13

Dear list, I was keeping this question in the back of my mind for several years so taking the occasion to reflect it now: Here follows the result of a simple benchmark of (exact->inexact n) and (exact->inexact (floor n)) where n is a flonum, fixnum or bignum integer, or rational. The code was executed in compiled form, with both safe and interrupts-enabled set and without any consideration to C compiler flags beyond -O1 , to reflect the environment of a typical application (not for instance a specialized number crunching environment). I remember a conversation on this topic like ~4y ago but don't remember any conclusion from it. Looking at these numbers, I think they're great and all you can ask for, with two exceptions, being to-integer conversion of a flonum or integer bignum. To get a better idea I experimented with heap size and live percent setting with those two, and got about the same results. If you are aware of any definition of |->integer| that would perform much better, please feel free to share! Result: On a laptop CPU core, here's how many of the respective operation Gambit performs per second ->integer of an integer (fixnum) 13,804,449 ->integer of a flonum 260,932 (perhaps performs much better with another definition?) ->integer of a rational 10,130,272 ->integer of an integer (bignum) 598,228 (perhaps performs much better with another definition?) ->flonum of an integer (fixnum) 36,550,882 ->flonum of a flonum 47,756,845 ->flonum of a rational 334,976 ->flonum of an integer (bignum) 51,075,409 Test code: (declare (block) (standard-bindings) (extended-bindings)) (define (noop) (void)) (define (->integer n) (lambda () (inexact->exact (floor n)))) (define (->flonum n) (lambda () (exact->inexact n))) (define (test t #!optional (seconds 5)) (let* ((at 0) (th (thread-start! (make-thread (lambda () (let loop () (t) (set! at (fx+ at 1)) (loop))))))) (thread-sleep! seconds) (let ((r at)) (thread-terminate! th) (exact->inexact (/ r seconds))))) (define (noop-test) (test noop)) (define (->integer-test1) (test (->integer 5 ))) (define (->integer-test2) (test (->integer 5. ))) (define (->integer-test3) (test (->integer 10/7))) (define (->integer-test4) (test (->integer 1e25))) (define (->flonum-test1) (test (->flonum 5 ))) (define (->flonum-test2) (test (->flonum 5. ))) (define (->flonum-test3) (test (->flonum 10/7))) (define (->flonum-test4) (test (->flonum 1e25))) Test output: > (time (noop-test)) (time (noop-test)) 5040 ms real time 4932 ms cpu time (4896 user, 36 system) no collections 2112 bytes allocated 6 minor faults no major faults 57985446.4 > (time (->integer-test1)) (time (->integer-test1)) 5019 ms real time 4884 ms cpu time (4872 user, 12 system) no collections 1232 bytes allocated no minor faults no major faults 13804449. > (time (->integer-test2)) (time (->integer-test2)) 5000 ms real time 4792 ms cpu time (4656 user, 136 system) 81 collections accounting for 187 ms real time (120 user, 52 system) 1607420656 bytes allocated 5110 minor faults no major faults 260932.6 > (time (->integer-test3)) (time (->integer-test3)) 5015 ms real time 4888 ms cpu time (4872 user, 16 system) no collections 2240 bytes allocated no minor faults no major faults 10130272.8 > (time (->integer-test4)) (time (->integer-test4)) 5003 ms real time 4680 ms cpu time (4536 user, 144 system) 158 collections accounting for 401 ms real time (304 user, 60 system) 3110877424 bytes allocated no minor faults no major faults 598228.8 > (time (->flonum-test1)) (time (->flonum-test1)) 5011 ms real time 4740 ms cpu time (4460 user, 280 system) 297 collections accounting for 736 ms real time (524 user, 124 system) 5848140864 bytes allocated no minor faults no major faults 36550882.2 > (time (->flonum-test2)) (time (->flonum-test2)) 5001 ms real time 4840 ms cpu time (4800 user, 40 system) no collections 2088 bytes allocated no minor faults no major faults 47756845.8 > (time (->flonum-test3)) (time (->flonum-test3)) 5005 ms real time 4972 ms cpu time (4920 user, 52 system) 65 collections accounting for 147 ms real time (120 user, 16 system) 1286350504 bytes allocated no minor faults no major faults 334976.6 > (time (->flonum-test4)) (time (->flonum-test4)) 5002 ms real time 4876 ms cpu time (4848 user, 28 system) no collections 2080 bytes allocated no minor faults no major faults 51075409.8 2013/4/24 Bradley Lucier <lucier(a)math.purdue.edu> > On 04/24/2013 01:33 PM, Mikael wrote: > > Hi Brad! > > 2013/4/24 Bradley Lucier <lucier(a)math.purdue.edu> > >> On 04/24/2013 12:37 PM, Zhen Shen wrote: >> > > [...] > > >> > Now, doing (declare (flonum)) at the top level, does this stop gambit >> > from boxing flonums across function calls? >> >> No. Gambit keeps flonums unboxed inside a basic block, whenever there's >> a jump (or the possibility of a jump), Gambit boxes up all the >> still-needed flonums. >> > > What about fixnums, would they remain unboxed in a loop? > > > Yes. Fixnums are always "immediate" (not boxed) values. > > > > Also btw, are there any tricks that can be applied to make it keep > flonums and fixnums unboxed in loops, like, (declare (not > interrupts-enabled)) or (not safe)? > > > Use (declare (not safe)) and flonum-specific operations to keep flonums > unboxed in a basic block. There's no way to keep them unboxed across jumps. > (With generic operations, flonums are boxed even in a basic block.) > > Or, you can use an f64vector as an explicit "box" for your flonum and > write monstrous code like this. > > (define (Array-sum a) > (f64vector-ref (Array-reduce (lambda (result y) > (f64vector-set! result 0 (fl+ > (f64vector-ref result 0) y)) > result) > (f64vector 0.) > a) > 0)) > > Brad >

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Re: [gambit-list] Promises & lazy thunks
by Bradley Lucier 30 Avr '13

30 Avr '13

On Apr 29, 2013, at 4:11 PM, Jason Felice wrote: > Oh, why not enable by default? Because it's very slow---it forces every argument to every built-in procedure at the top of the procedure. > > (I ask because of the "check to see if it still works" comment.) Brad

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[ANN] Gambit-C v4.6.8 released
by gambit＠iro.umontreal.ca 30 Avr '13

30 Avr '13

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problem with binding to glfw
by Cyrille Duret 30 Avr '13

30 Avr '13

hello, I have a weird error message and I could not understand what's the source of this error and how to fix it. A simple example : glfw-ffi.scm : (c-declare "#include \"GL/glfw.h\"") (define glfwInit (c-lambda () int "glfwInit")) compilation : $ export GAMBC_CC_VERBOSE=yes $ gsc -ld-options "-L/usr/local/lib -lglfw" glfw-ffi.scm gcc -Wno-unused -Wno-write-strings -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fomit-frame-pointer -fno-move-loop-invariants -fPIC -fno-common -mieee-fp -rdynamic -shared -D___SINGLE_HOST -D___DYNAMIC -I"/usr/local/Gambit-C/include" -o "glfw-ffi.o2" glfw-ffi.c -L/usr/local/lib -lglfw $ gsc Gambit v4.6.7 > (load "glfw-ffi") Unable to find pthread_mutexattr_setkind_np versioned symbol. Aborting. Abort(coredump) $ Anyone see this problem with pthread ? thanks a lot cyrille

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Gambit-list Avril 2013