Gambit-list Novembre 2011

gambit-list@iro.umontreal.ca

12 participants
27 discussions

Edge triggered I/O with libevent
by Adam Langley 04 Avr '13

04 Avr '13

Gambit uses the select call on POSIX systems to multiplex IO operations. This is fine for small numbers of file descriptors, but falls apart quickly with large numbers[1]. libevent[2] is a wrapper library around a number of modern IO multiplexing systems (epoll on Linux, kqueue on the BSDs as well as poll and select). Attached is a patch which converts Gambit to using edge triggered I/O with epoll and libevent. This also requires a patch (attached) of libevent since the standard distribution doesn't include edge triggering support and the upstream appears to be on holiday. (epoll is required because I don't have a BSD box on which to develop edge triggering support for kqueue) This patch (for Gambit) preprocesses away to nothing unless --enable-libevent is passed to the configure script. (Note that, since this patches the configure.ac script, you'll need to run autoconf to regenerate). I hope I've not broken anything, but at this stage I've only tested that the console and tcp ports work. This patch (in the future) should also allow people, who write programs which use socket calls directly, to integrate into the main event loop at some point. Testing is more than welcome and, if you find a form of IO which is broken, please email me. [1] http://monkey.org/~provos/libevent/libevent-benchmark2.jpg [2] http://monkey.org/~provos/libevent/ -- Adam Langley agl(a)imperialviolet.org http://www.imperialviolet.org (+44) (0)7906 332512 PGP: 9113 256A CC0F 71A6 4C84 5087 CDA5 52DF 2CB6 3D60

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How to ue a module?
by Hendrik Boom 25 Jan '12

25 Jan '12

I just made bootstrap from the 4.6.1 development sources, which I downloaded using git. When I start gsi and, according to the section "Subdivide code into modules" in the tour of Scheme in Gambit, I use "use" it tells me hendrik@notlookedfor:~/dv/lang/gambit/gambit$ gsi/gsi Gambit v4.6.1 > (use ssax-sxml) *** ERROR IN (console)(a)1.2 -- Unbound variable: use 1> So evidently something is still missing, unconfigured, unbuilt, or whatever. It doesn't even get around to looking for the library -- which is another question: how does it find the libraries, assuming it gets that far. And if the X module system is itself a module, how do I bootstrap it into the system? Or should I be using an entirely different mechanism? -- hendrik

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How to pass a Scheme string to a const char*?
by Vok Vojwo 21 Déc '11

21 Déc '11

I have defined wrappers for openlog and syslog. The openlog function requires an ident string. Whatever I pass to openlog does not survive until a call to syslog. I have tried to protect the string with ##still-copy (with and without box/unbox) but it does not work. Here is the example: (define const-ident #f) (define openlog (let ((openlog (c-lambda (char-string int int) void "openlog"))) (lambda (ident option facility) (set! const-ident (box (##still-copy ident))) (openlog (unbox const-ident) option facility)))) (define syslog (let ((syslog (c-lambda (int nonnull-char-string) void "syslog"))) (lambda (priority . args) (syslog priority (apply string-append args))))) This program: (define (main . args) (openlog "gambit" (+ LOG_NDELAY LOG_PID) LOG_USER) (syslog LOG_INFO "hello") (closelog)) will generate random syslog tags: Nov 21 17:58:49 sn-e0692 ��*#002[11621]: hello What is the correct way to protect a string to be able to pass it to a const char* argument?

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Gambit REPL and MSLUG presentations
by Marc Feeley 28 Nov '11

28 Nov '11

Hello all. Here are the PDFs of the presentations I gave at the MSLUG last thursday. http://www.iro.umontreal.ca/~gambit/Gambit-REPL.pdf http://www.iro.umontreal.ca/~gambit/Distributed-computing-with-Gambit.pdf Moreover, the code of the demo can be found here: http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Script:MSLUG:teleport… Note that the demo can be executed on Gambit REPL and on the "plain" Gambit. Heterogeneous networks are not a problem... threads can teleport from one platform type (such as an ARM based iPhone) to a platform of another type (such as an x86 Windows). Have fun! Marc

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Put Gambit-internal .h files in a standard filesystem location?
by Mikael 28 Nov '11

28 Nov '11

Dear Marc, This is not a very high prio thing in any way, but I wanted to query you about it in consideration of consistency at some level; for some purposes in Gambit use, you need access to Gambit's internal .h files (os.h os_io.h os_time.h etc.) from a C include in a scheme file. In case Gambit is intended for this never be the case, please tell; for looking up fds of ports at least it's needed today. Do you currently have any convention for a path in the filesystem where this should be stored, and where "make install" or alike with the rigth arguments, copies them? Up to now I went with /usr/local/Gambit-C/lib/ i.e. /usr/local/Gambit-C/lib/os_io.h etc. for them, and got them there by the means of manual copying. Kind regards, Mikael

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(no subject)
by Mikael 24 Nov '11

24 Nov '11

Thanks for Gambit again, Marc! (45 days post ca thanksgiving) It will be great to see the upcoming developments. Mikael

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cast scheme procedure to c function
by Álvaro Castro-Castilla 22 Nov '11

22 Nov '11

Hi! I'm trying to make a procedure that takes one argument (another procedure) and converts it to a C function, assigning it to a function pointer in C. Then I want to call that function from that pointer in C. I'm aware that the typical way to do this is with c-declare in a static way, but I need to be able to achieve the same without using c-declare. My current attempt: (define (uno) 1) (define bind (c-lambda (scheme-object) void "simple_callable = ___CAST(void (*)(),___arg1);")) (bind uno) ...then the C part, same file: // before void (*simple_callable)(void); // after (bind uno) is executed (*simple_callable)(); I guess that I'm doing either the input type or the cast (or both) wrong. Probably I'm assuming to much simply casting a "scheme-object" to a void(*)(). Is this what I'm trying to do even possible? Thanks a lot! Álvaro

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How to c-lambda printf?
by Vok Vojwo 22 Nov '11

22 Nov '11

I am searching for a way to specify a variable argument list in c-lambda to use functions like printf in Scheme. Is there a way?

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can't find ___main_char
by Hendrik Boom 18 Nov '11

18 Nov '11

Working from gambc-v4_6_1-devel.tgz configure went fine. Fore reference, teh command was ./configure --enable-multiple-versions --enable-single-host --enable-gcc-opts ---enable-cplusplus --enable-shared but it failed on make. I got lots of warnings about warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] a few of warning: "__USE_LARGEFILE64" redefined [enabled by default] and at the end, g++ -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mieee-fp -rdynamic -I"../include" -o "gsi" _gsi.o _gsi_.o "../lib/libgambc.so" -lutil -ldl libgambcgsi.so _gsi_.o: In function `main': _gsi_.c:(.text+0x47): undefined reference to `___main_char' collect2: ld returned 1 exit status make[1]: *** [gsi] Error 1 make[1]: Leaving directory `/home/hendrik/dv/lang/gambit/gambit/gsi' make: *** [all-recursive] Error 1 hendrik@notlookedfor:~/dv/lang/gambit/gambit$ Now the symbol ___main_char occurs in os_base.c. Here's the output from compiling os_base.c. Let me know if you need the full compilation log. It's rather long and tedious. g++ -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fmodulo-sched -freschedule-modulo-scheduled-loops -fomit-frame-pointer -fPIC -fno-common -mieee-fp -I"../include" -c -o "os_base.o" -I. -DHAVE_CONFIG_H -D___GAMBCDIR="\"/usr/local/Gambit-C/v4.6.1\"" -D___SYS_TYPE_CPU="\"i686\"" -D___SYS_TYPE_VENDOR="\"pc\"" -D___SYS_TYPE_OS="\"linux-gnu\"" -D___CONFIGURE_COMMAND="\"./configure --enable-multiple-versions --enable-single-host --enable-gcc-opts --enable-cplusplus --enable-shared\"" -D___OBJ_EXTENSION="\".o\"" -D___EXE_EXTENSION="\"\"" -D___BAT_EXTENSION="\"\"" -D___PRIMAL os_base.c -D___LIBRARY In file included from os_base.h:8:0, from os_base.c:13: os.h:1043:0: warning: "__USE_LARGEFILE64" redefined [enabled by default] /usr/include/features.h:280:0: note: this is the location of the previous definition os_base.c: In function ‘void ___fatal_error(char**)’: os_base.c:630:21: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:637:23: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c: At global scope: os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1099:1: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c: In function ‘int ___os_err_code_to_string(int)’: os_base.c:1194:21: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1200:21: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings] os_base.c:1248:15: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]

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'-expansion' code doesn't match .c file
by Bradley Lucier 17 Nov '11

17 Nov '11

Marc: Here's a simple benchmark harness plus two tests: (declare (standard-bindings) (extended-bindings) (block)) (declare (inline)) (define (inline-unsafe-flonum-+ x y) (declare (not safe) (flonum)) (+ x y)) (define (inline-safe-flonum-+ x y) (declare (flonum)) (+ x y)) (define-macro (test fn x y) (define (extend-name fn) (string->symbol (string-append "test-" (symbol->string fn)))) `(begin (define (,(extend-name fn) x y) (declare (not safe)) (let outer-loop ((x x) (y y) (number-of-tests 2) (begin-time #f) (i #f)) (##gc) (let inner-loop ((x x) (y y) (number-of-tests number-of-tests) (begin-time (cpu-time)) (i 0)) (if (fx< i number-of-tests) (begin (let () (declare (inlining-limit 10000)) (,fn x y)) (inner-loop x y number-of-tests begin-time (fx+ i 1))) (let ((run-time (fl- (cpu-time) begin-time))) (if (fl< 1.0 run-time) (pp (list (fl/ (exact->inexact number-of-tests) run-time) '(,fn x y) )) (outer-loop x y (fx* 2 number-of-tests) begin-time #f))))))) (,(extend-name fn) ,x ,y))) (test inline-unsafe-flonum-+ 2. 3.) (test inline-safe-flonum-+ 2. 3.) Here's the compiled output: heine:~/programs/gambc-v4_6_2-devel> gsc -c -expansion crap-test+.scm Expansion: (define inline-unsafe-flonum-+ (lambda (x y) ('#<procedure #2 ##fl+> x y))) (define inline-safe-flonum-+ (lambda (x y) (if (and ('#<procedure #3 ##flonum?> y) ('#<procedure #3 ##flonum?> x)) ('#<procedure #2 ##fl+> x y) ('#<procedure #4 fl+> x y)))) (define test-inline-unsafe-flonum-+ (lambda (x y) (letrec ((outer-loop (lambda (x y number-of-tests begin-time i) (let ((begin-temp.1 (##gc))) (letrec ((inner-loop (lambda (x y number-of-tests begin-time i) (if ('#<procedure #5 ##fx<> i number-of-tests) (let ((begin-temp.0 (let ((x x) (y y)) ('#<procedure #2 ##fl+> x y)))) (inner-loop x y number-of-tests begin-time ('#<procedure #6 ##fx+> i 1))) (let ((run-time ('#<procedure #7 ##fl-> (cpu-time) begin-time))) (if ('#<procedure #8 ##fl<> 1. run-time) (pp ('#<procedure #9 ##list> ('#<procedure #10 ##fl/> (if ('#<procedure #11 ##fixnum?> number-of-tests) ('#<procedure #12 ##fl<-fx> number-of-tests) (if ('#<procedure #3 ##flonum?> number-of-tests) number-of-tests ('#<procedure #13 exact->inexact> number-of-tests))) run-time) '(inline-unsafe-flonum-+ x y))) (outer-loop x y ('#<procedure #14 ##fx*> 2 number-of-tests) begin-time #f))))))) (inner-loop x y number-of-tests (cpu-time) 0)))))) (outer-loop x y 2 #f #f)))) (test-inline-unsafe-flonum-+ 2. 3.) (define test-inline-safe-flonum-+ (lambda (x y) (letrec ((outer-loop (lambda (x y number-of-tests begin-time i) (let ((begin-temp.3 (##gc))) (letrec ((inner-loop (lambda (x y number-of-tests begin-time i) (if ('#<procedure #5 ##fx<> i number-of-tests) (let ((begin-temp.2 (let ((x x) (y y)) (if (and ('#<procedure #3 ##flonum?> y) ('#<procedure #3 ##flonum?> x)) ('#<procedure #2 ##fl+> x y) ('#<procedure #4 fl+> x y))))) (inner-loop x y number-of-tests begin-time ('#<procedure #6 ##fx+> i 1))) (let ((run-time ('#<procedure #7 ##fl-> (cpu-time) begin-time))) (if ('#<procedure #8 ##fl<> 1. run-time) (pp ('#<procedure #9 ##list> ('#<procedure #10 ##fl/> (if ('#<procedure #11 ##fixnum?> number-of-tests) ('#<procedure #12 ##fl<-fx> number-of-tests) (if ('#<procedure #3 ##flonum?> number-of-tests) number-of-tests ('#<procedure #13 exact->inexact> number-of-tests))) run-time) '(inline-safe-flonum-+ x y))) (outer-loop x y ('#<procedure #14 ##fx*> 2 number-of-tests) begin-time #f))))))) (inner-loop x y number-of-tests (cpu-time) 0)))))) (outer-loop x y 2 #f #f)))) (test-inline-safe-flonum-+ 2. 3.) Now see that ('#<procedure #2 ##fl+> x y)) is in the expansion of each test loop (at begin-temp.0 and begin-temp.2), but that addition is not in the C-code (presumably because it is not referenced). It's OK with me that the compiler removes this code; what I find troubling is that it's still in the "expansion" of the scheme code---it appears that there are optimizations done after the expansion but before code generation. I'd like to rely on the output of '-expansion' more and to rely on reading the C code (or the resulting assembly code in extreme cases) less in trying to figure out how gsc will compile my code. Can the '-expansion' be emitted later in the compilation process, after all code-visible optimizations have been made? Brad

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Gambit-list Novembre 2011