Gambit-list Mai 2007

gambit-list@iro.umontreal.ca

25 participants
42 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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Please don't delete the .c file
by Bradley Lucier 06 Fév '08

06 Fév '08

Marc: I needed to debug a gsc-compiled file with gdb today, and it was fairly inconvenient that the .c file wasn't left around by compile- file in beta 21. I suggest that the .c file be left around for the various source tools that need it. Brad

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Re: [gambit-list] compiler bug?
by Marc Feeley 03 Sep '07

03 Sep '07

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 25-Sep-06, at 3:48 PM, Sven.Hartrumpf(a)FernUni-Hagen.de wrote: > Hello Marc. > > I have a large program which behaves a little different > with gsc than any other Scheme I know of (bigloo, chicken, gauche): > Here is the problematic region: > > (let* ((orth (and (pair? word-info) > ;(not (eq? (caar word-info) 'words)) > (fs-value (car word-info) '(orth)))) > (orth-l (if orth (string-length orth) 0)) > (left-hyphen (and (> orth-l 2) > (char=? (string-ref orth 0) # > \-))) ; examples: \quw{Steuergesetzgebung und -verwaltung}, \quw > {auspringen und -setzen} > (right-hyphen (and (> orth-l 1) > (char=? (string-ref orth (- orth- > l 1)) #\-))) > (step (if left-hyphen > (and (not right-hyphen) > -1) > (and right-hyphen > 1)))) > > left-hyphen and right-hyphen are evaluated to #f for some binding - > this > is as expected. But step is bound to 1 which seems wrong to me. > Minimizing the problem might be hard for me, so I hope that you can > see > the problem already :-) > > Ciao > Sven Sven, you have just uncovered a nasty bug in the compiler. In beta 18 the transformation for the "and" form is too aggressive in the case where the second argument is a constant. As far as I can tell this bug was introduced just before beta 18 was released. Surprisingly in the 70Kloc in the Gambit runtime system and compiler this case does not occur. I have now fixed the bug and will release beta 19 shortly because this is a serious bug. Thanks! Marc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (Darwin) iD8DBQFFGEqS//V9Zc2T/v4RAqTeAJ9asp7elGoK7yqa6MzmLFTRj6K8UwCfc3d4 5haROCNvlgMs1NREyZCgYIw= =bvLI -----END PGP SIGNATURE-----

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Flushing not done ?
by Adrien Pierard 31 Mai '07

31 Mai '07

Hello ! I've been writing some code today, dumping data in files on the hard disk. I knew that gambit, and many (if not all) languages buffers data before enventually writing it to the disk. What puzzled me today, is that it actually never got written ! Here is the code : (let ((o (open-output-file "/tmp/flushed-data"))) (display "whirl" o) (display "\n" o)) I thought that when the gambit process cleanly finishes, it would flush the port, though it didn't. I had to append a (close-output-port o) in order to have my data dumped. So, is that an undocumented feature, do I have to do the display in the IO monad ? Or is it just fully compliant with the "do what you want with the little constraint in the RnRS" ? This behaviours happens as well with interpreted code as woth compiled code. Isn't the OS (or the libc behind gambit) supposed to flush when the process terminates ? Should I stick to CALL-WITH-OUPUT-FILE or always close ports ? Adrien -- " am not a Church numeral; I am a free variable!" (The Scheme Underground)

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compile-file + 0 args c-lambda + syntax-case
by Phil Dawes 31 Mai '07

31 Mai '07

Hi Marc, Hi gambit people, I'm not sure how fixable this is, but if I try to use 'compile-file' to compile a file containing a c-lambda that has no arguments, from an environment with syntax-case loaded then I get the following error: *** ERROR IN map -- invalid syntax () If the c-lambda has arguments then it works. If syntax-case isn't loaded then it works also. E.g. ------ c.scm ----- (define get-value (c-lambda () (int32) "___result = 35;")) ------------------- $ gsc - > (compile-file "c") #t > (load "~~/syntax-case.scm") "/usr/local/Gambit-C/4.0b22/syntax-case.scm" > (compile-file "c") *** ERROR IN map -- invalid syntax () This is in gambit-4.0b22 on x86 linux BTW. Also, while I'm here, is there a better way to reveal the value of things to scheme from C? In particular I want to be able to get a pointer to a C function so that it can be passed to bsearch. Many thanks, Phil

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Comparing gambit bignums with gmp 4.2.1
by Bradley Lucier 30 Mai '07

30 Mai '07

I'll get these comparisons out now before gmp 5 comes out ;-). Here are some comparisons with gmp for large integers. This is with the _num.scm I sent you earlier. (define a (time (expt 3 2095903))) (define b (time (expt 7 1183294))) (define c (time (expt 11 1920505))) I chose these numbers because they were used in a talk by Paul Zimmermann; I presume he chose them because > (map integer-length (list a b c (expt 10 1000000))) (3321928 3321927 6643856 3321929) I believe that on smaller numbers gmp should be significantly faster than gambit. On my laptop (1.67GHz PowerPC 7450, gcc 4.1.2, 32 bit), times in seconds Gambit GMP 4.2.1 (* a b) .907 .40 (quotient c a) 4.176 1.70 (integer-sqrt c) 4.179 1.35 (gcd a b) 55.494 224.31 On my desktop (2.0GHz PowerPC 970, gcc 4.1.2, 64 bit): (* a b) .352 .13 (quotient c a) 1.744 .59 (integer-sqrt c) 1.813 .46 (gcd a b) 24.071 36.56 On a server (2.2GHz Opteron, gcc 4.1.2, 64 bit): (* a b) .344 .17 (quotient c a) 1.550 .73 (integer-sqrt c) 1.526 .57 (gcd a b) 17.713 31.34 GMP was compiled with gcc -O3 -mcpu=970 -m64 -o test test.c -I/pkgs/gmp-4.2.1-64/include/ - L/pkgs/gmp-4.2.1-64/lib -lgmp and similarly for the other machines. Brad

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Re: [gambit-list] problem compiling gambit
by Gabriel Filion 29 Mai '07

29 Mai '07

Great! it worked well. thank you :) David St-Hilaire wrote: > Hi Gabriel! > > I had the same problem the other day. After looking into the problem > with Marc, he came to the conclusion that the thing to do is to add some > ___BEGIN_C_LINKAGE and ___END_C_LINKAGE at the problematic position in > lib/os.h, so you'd get something like: > > #ifdef USE_environ > ___BEGIN_C_LINKAGE > extern char **environ; > ___END_C_LINKAGE > #endif > > I hope this will resolve your problem! > > David > -- Gabriel Filion

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problem compiling gambit
by Gabriel Filion 29 Mai '07

29 Mai '07

Hello, I have a problem compiling gambit, it says a definition in unistd.h redefines something. gabster@barbiche:~/local/gambc-4.0b22$ ./configure --prefix=/home/gabster/local/gambit/ --enable-single-host --enable-cplusplus [ ... ] gabster@barbiche:~/local/gambc-4.0b22$ make making all in include make[1]: Entering directory `/home/gabster/local/gambc-4.0b22/include' make[1]: Leaving directory `/home/gabster/local/gambc-4.0b22/include' making all in lib make[1]: Entering directory `/home/gabster/local/gambc-4.0b22/lib' g++ -I../include -I. -Wall -W -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fexpensive-optimizations -fforce-addr -fpeephole2 -falign-jumps -falign-functions -fno-function-cse -ftree-copyrename -ftree-fre -ftree-dce -fregmove -fgcse-las -freorder-functions -fcaller-saves -fno-if-conversion2 -foptimize-sibling-calls -fcse-skip-blocks -funit-at-a-time -finline-functions -fomit-frame-pointer -fPIC -fno-common -mieee-fp -DHAVE_CONFIG_H -D___PRIMAL -D___LIBRARY -D___GAMBCDIR=\"/home/gabster/local/gambit//4.0b22\" -c _io.c g++ -I../include -I. -Wall -W -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fexpensive-optimizations -fforce-addr -fpeephole2 -falign-jumps -falign-functions -fno-function-cse -ftree-copyrename -ftree-fre -ftree-dce -fregmove -fgcse-las -freorder-functions -fcaller-saves -fno-if-conversion2 -foptimize-sibling-calls -fcse-skip-blocks -funit-at-a-time -finline-functions -fomit-frame-pointer -fPIC -fno-common -mieee-fp -DHAVE_CONFIG_H -D___PRIMAL -D___LIBRARY -D___GAMBCDIR=\"/home/gabster/local/gambit//4.0b22\" -c _num.c g++ -I../include -I. -Wall -W -Wno-unused -O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv -fexpensive-optimizations -fforce-addr -fpeephole2 -falign-jumps -falign-functions -fno-function-cse -ftree-copyrename -ftree-fre -ftree-dce -fregmove -fgcse-las -freorder-functions -fcaller-saves -fno-if-conversion2 -foptimize-sibling-calls -fcse-skip-blocks -funit-at-a-time -finline-functions -fomit-frame-pointer -fPIC -fno-common -mieee-fp -DHAVE_CONFIG_H -D___PRIMAL -D___LIBRARY -D___GAMBCDIR=\"/home/gabster/local/gambit//4.0b22\" -c _std.c os.h:537: error: previous declaration of ‘char** environ’ with ‘C++’ linkage /usr/include/unistd.h:500: error: conflicts with new declaration with ‘C’ linkage make[1]: *** [_std.o] Error 1 make[1]: Leaving directory `/home/gabster/local/gambc-4.0b22/lib' make: *** [all-recursive] Error 1 am I missing some library or anything else? I just reinstalled my computer and before doing so, I was able to compile gambit-4.0b22 with the same options to configure without a problem. -- Gabriel Filion

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how to exec shell command then collect result as a string? (like with perl $a=`ls`; )
by Naruto Canada 27 Mai '07

27 Mai '07

hi how to exec shell command then collect result as a string? (like with perl $a=`ls`;) I need to call maple and collect the result. shell-command seems to return only exit status. Thanks Ask a question on any topic and get answers from real people. Go to Yahoo! Answers and share what you know at http://ca.answers.yahoo.com

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Revision control systems Scheme interface
by Guillaume Cartier 25 Mai '07

25 Mai '07

The post by Christian where he talked about doing a Scheme interface to GIT has made me realize how useful a scheme interface to a good revision control system would be in my projects. If enough people feel the same way, maybe we could start a small project and build one. It should not be a lot of work. Anyone knows about any Scheme interface in existence that could give us a head start? Also, it should not be too hard to support many revision control systems by building the interface in a generic fashion that would delegate to specific interfaces. Guillaume

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Gambit-list Mai 2007