Gambit-list Mars 2008

gambit-list@iro.umontreal.ca

34 participants
49 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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New Gambit wiki
by Marc Feeley 18 Mai '08

18 Mai '08

I have just installed a recent distribution of MediaWiki and PHP, and the reCaptcha extension. In order to do this I had to use a different machine (dynamo.iro.umontreal.ca) and copy all the pages from the old wiki to the new wiki. When a page edit is saved a visual captcha will now appear to make sure the edit has been submitted by a human user. Please let me know if you find broken links, missing information, or other issues. Marc

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Problem with shared libs and Gambit.
by Panagiotis Christopoulos 16 Avr '08

16 Avr '08

Hi everybody, I'm a contributor in Gentoo Lisp Project, and we have problems with gambit, when --enable-shared is ON. I studied a little your makefiles, and I saw that with --enable-shared, what make's, "install" target does, is to install lib files in their $(prefix)/lib/ directory, and then it tries to create the executables gsi and gsc and link them with those libs which must be in their installation path. For us it leads to this: --------- (chroot-working) (muse) Calliope gambc-v4_2_5 # ldd `which gsi` linux-vdso.so.1 => (0x00007fffa39fd000) /var/tmp/portage/dev-scheme/gambit-4.2.5/image/usr/lib64/libgambcgsi.so => not found /var/tmp/portage/dev-scheme/gambit-4.2.5/image/usr/lib64/libgambc.so => not found libutil.so.1 => /lib/libutil.so.1 (0x00002b7a0737d000) libdl.so.2 => /lib/libdl.so.2 (0x00002b7a07580000) libm.so.6 => /lib/libm.so.6 (0x00002b7a07784000) libc.so.6 => /lib/libc.so.6 (0x00002b7a07a03000) /lib64/ld-linux-x86-64.so.2 (0x00002b7a07161000) (chroot-working) (muse) Calliope gambc-v4_2_5 # --------- (/var/tmp/portage/dev-scheme/gambit-4.2.5/image/ is our fake directory for the package creation process.) I'm not an expert in your build system, and I find it difficult to patch it my own, to make it respect $(DESTDIR) instead of just $(prefix), so I was wondering if gambit's developers, can do something about that (maybe use libtool, or change a little the build system in a next release). I think that the affected code has to do with $(LINK_FOR_INSTALL_LIBS) variable. I hope I didn't bother you, Panagiotis(pchrist)

2 1

Strange Networking Bug on MinGW (LONG)
by François Magnan 04 Avr '08

04 Avr '08

Hi, I worked hard to isolate one of my bugs and I found a rather disturbing minimal example that reproduces the bug. It can be observed in all the latests versions of Gambit (including 4.2.1). Basically, I start a minimal multithread web server and in another thread I start a loop that calls a serie of open-tcp-client to different ips in the local network. The default web browser is launched to get the page served by the web server. On MacOSX Leopard everything is fine. On WindowsXP (MingW compiled version of Gambit) the page takes an unnaceptable loooong time to load. The website index.html must require multiple HTTP GET to render (a page with multiple pictures for example). What is the most disturbing is that if I replace the calls to "read-u8- line" by simple "read-line", the bug disapears. The bug is therefore somehow related to "read-u8". Here is the sample code. You have to define "Server-ROOT" at the top so it points to a website on your local hard-drive. I didn't try on Linux but to try it the code will have to be adapted a little bit (how to launch the default browser on Linux?). What could lead to this huge difference between a sequence of read-u8 and read-line on WinXP??? Thank you, Francois Magnan ;;; Gambit Networking Test Example ;;; ;;; Minimal web server that gets incredibly slow on WinXP (MinGW) if it is run in parallel with another thread that does a network scan. ;;; ;;; If the "read-u8-line" calls are replaced by "read-line" the bug disapears. ;;; ;;; On MacOSX Leopard the bug is not present. ;;; ;;; Was tested with versions: Gambit-C 4.0.1, 4.1.2, 4.2.1 ;;; ;;; ;;;; Server-ROOT ;;; ;;; ******************* ;;; Put here the path to a static website with many files to load to render index.html ;;; ******************* ;(define Server-ROOT "/Users/magnan/TELOS/interface/TELOS-Desktop") (define Server-ROOT "C:/TELOS/interface/TELOS-Desktop") ;;; ;;;; main ;;; (define (main) (start-server) (start-broadcast) (start-client) ) ;;; ;;;; Minimal Web Server ;;; (define (start-server) (let ((rpc-command-queue (open-tcp-server (list port-number: 8000)))) (thread-start! (make-thread (lambda () (let loop () (let ((incoming-connection (read rpc-command-queue))) (force-output) (serve-connection incoming-connection)) (loop))))))) (define (serve-connection incoming-connection) (thread-start! (make-thread (lambda () (let* ((line (read-u8-line incoming-connection)) (splitted (split-string line #\space)) (path (cadr splitted))) (read-all-headers incoming-connection) (force-output) (with-exception-catcher (lambda (e) (##display-exception e (current-output-port))) (lambda () (serve-file path incoming-connection)))))))) (define (read-all-headers incoming-connection) (let ((line (read-u8-line incoming-connection))) (pp (list "read header line" line)) (force-output) (if (not (equal? line "")) (read-all-headers incoming-connection)))) (define (split-string str sep-char) (call-with-input-string str (lambda (p) (read-fields p sep-char #f)))) (define (read-fields port sep inc-sep?) (read-all port (lambda (p) (read-line p sep inc-sep?)))) (define (serve-file path incoming-connection) (let* ((complete-path (string-append Server-ROOT path)) (fileInfo (file-info complete-path)) (size (file-info-size fileInfo)) (mimetype (compute-mimetype complete-path)) (header (compute-get-result-header size mimetype))) (display header incoming-connection) (output-file-data complete-path incoming-connection) (close-port incoming-connection))) (define (compute-get-result-header size mimetype) (string-append "HTTP/1.0 200 OK\r\n" "Content-type: " mimetype "\r\n" "Content-length: " (number->string size) "\r\n" "\r\n")) (define (output-file-data filePath connection) (with-input-from-file filePath (lambda () (letrec ((output-file-data-rec (lambda () (let ((rc (read-char))) (if (not (equal? rc #!eof)) (begin (write-char rc connection) (output-file-data-rec))))))) (output-file-data-rec))))) (define (compute-mimetype filePath) (let* ((ext (path-extension filePath)) (rext (and (string? ext) (substring ext 1 (string-length ext))))) (case (string->symbol rext) ((jpg jpeg JPG JPEG) "image/jpeg") ((gif GIF) "image/gif") ((png PNG) "image/png") ((html HTML htm HTM) "text/html") ((js JS) "text/javascript") ((css CSS) "text/css") (else "application/octet-stream" )))) ;;; ;;;; start-broadcast ;;; (define (start-broadcast) (thread-start! (make-thread (lambda () (let* ((hostname (host-name)) (hi (host-info hostname)) (host-ips (host-info-addresses hi)) (host-ip (car host-ips))) (letrec ((network-broadcast (lambda (i) (if (= i 255) #t (begin (u8vector-set! host-ip 3 i) (call-addr host-ip) (thread-sleep! 0.2) (network-broadcast (+ i 1))))))) (network-broadcast 1))))))) (define (call-addr target-addr) (pp (list "trying to reach" target-addr)) (with-exception-catcher (lambda (e) #f) (lambda () (let ((port (open-tcp-client (list server-address: target-addr port-number: 5000)))) (with-exception-catcher (lambda (e) #f) (lambda () (input-port-timeout-set! port 0.1) (output-port-timeout-set! port 0.1) (write (list 1 2 3) port))) (close-port port))))) ;;; ;;;; Client ;;; (define (start-client) (if (equal? (get-host-os) "WinXP") (shell-command "start http://localhost:8000/index.html") (shell-command "open \"http://localhost:8000/index.html\""))) (define (get-host-os) (with-exception-handler (lambda (e) "WinXP") (lambda () (let* ((p (open-process '(path: "/usr/bin/uname" arguments: ("-s")))) (r (read-line p))) (close-port p) r)))) ;;; ;;;; read-u8-line ;;; (define (read-u8-line port) (letrec ((read-loop (lambda (acc) (let ((b (read-u8 port))) (if (or (equal? b 13) (equal? b 10) (equal? b #!eof)) (begin (read-u8 port) acc) (read-loop (string-append acc (list- >string (list (integer->char b)))))))))) (read-loop ""))) ;;; ;;;; start main ;;; (main)

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"Contribute to Scheme module system" (Re: soc project idea)
by Christian Jaeger 31 Mar '08

31 Mar '08

Hello Lispers of NYC Sorry for coming so late to the game. We've recently started an effort implementing a module system for Scheme with the primary aim to be open to several modularization approaches. We have written a page about this at: http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Module_System It's interesting to see the other module system proposals (Lexicons, PLT-alike module system on CL, R6RS on Gambit). I think there could be ways to benefit each other, or maybe even partly collaborating: * Lexicons: especially the approach for lexical value capturing in macros strikes me as interesting, we could try this out in our system, too. Also the first class environment handling is interesting as being very interaction centered. * PLT-alike module system on CL: maybe a second student could work with us on creating a port of that system with our guidance on top of our current module infrastructure to Gambit. That would be a useful first way to stretch our infrastructure and understanding and potentially even deliver a way to run PLT-Scheme modules on Gambit. BTW: wondering why you choose PLT, and not e.g. the Scheme-48 module system? * R6RS on Gambit: a long term goal would be to run R6RS on top of / as plugin of our generalized module system. Probably not so quick, though, but it would be worthwhile to chat every now and then about what each other's doing already during this summer. Your feedbacks are welcome. Christian. PS. I'm away now for 4 hours, and then will read mail and be in IRC in #gambit, #scheme, and #summeroflisp on freenode. system user wrote: > name: Christian Jaeger > email: christian(a)pflanze.mine.nu > proj_name: Contribute to Scheme module system > short_desc: Implement one modularization approach, or several alternative tasks with us > skills: Good knowledge in functional and better also object oriented programming; have ideas what module systems should be about > level: 4 >

2 2

The web-repl, REPL output channels, and debugging
by Derek Peschel 30 Mar '08

30 Mar '08

A message from November 2006 explains the issue of REPL channels, which are assigned to threads when they try to do input or output. I have (repl-result-history-max-length-set! 10) in my .gambcini file, and according to my tests that is enough to assign a REPL channel to the primordial thread, which means the primordial-thread version of the startup code in web-repl.scm won't work (I/O goes to the UNIX terminal that started gsi). Is there any way to do the same customization without assigning the channel? The threaded version of the startup code has a different problem. I run the server and the client, and the first-level REPL appears in the client window. If I send input that causes an error, the second- level REPL doesn't appear in the client window or at the server's terminal. Interestingly, I can use ^C at the server's terminal to interrupt the client, and each time some thread-switching logic assigns a new thread (but not the second-level REPL I want) to the client. -- Derek

1 0

Compiling Gambit programs under Windows...
by Philippos Apolinarius 28 Mar '08

28 Mar '08

I would like to compile Gambit programs on Windows. I have installed a minimum gcc, that I use to compile Lisp, Maxima, Bigloo, Stalin, and other languages that compile through C. I tried to compile Gambit programs, to no avail. Here is what I have done: gsc test.scm This generates the file test.o1, that I can load from the interpreter. However, I cannot use interpreted code (or large distribution files, btw) for assignments. The nex thing I tried was... gsc -link test.scm This gives me test.c test_.c. The manual says that I should compile these files, but do not tell how to do it for Windows (there are examples for Mac OS-X, and Linux). I tried: gcc -lgambc -lm test.c test_.c I get a large number of errors, and that is all. --------------------------------- Ask a question on any topic and get answers from real people. Go to Yahoo! Answers.

4 3

syntax-case and #!optional/#!rest
by William Cook 28 Mar '08

28 Mar '08

I like to use syntax-case because it is more portable with other schemes. But it seems that it interferes with #!optional and #!rest. Is there any way around this? Can I use some kind of scoping/module approach to allow me to mix libraries that use #!optional with define-syntax? William

1 0

BLAS and FFTW3 packages in dumping grounds
by Pierre-Alexandre Fournier 28 Mar '08

28 Mar '08

Hi, for those of you interested in numerical analysis, I've added Gambit Scheme interfaces to high-performance BLAS and FFTW3 libraries in the Dumping Grounds: http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Dumping_Grounds The BLAS interface is a complete wrapper for level 1, 2 and 3 BLAS linear algebra routines. The FFTW3 interface is a wrapper for some FFTW3 functions (float or double, real or complex, uni or multi-dimensional FFT functions). Cheers, -- Pierre-Alexandre

2 1

c-lambda behaviour...
by David St-Hilaire 26 Mar '08

26 Mar '08

Hello! In a simple example, I saw a weird or unexpected (from me) behaviour from the c-lambda function. Here is what I did: (c-declare "#include <stdio.h>") ((c-lambda () void "printf(\"test: %d\\n\", 10);") This worked just fine, but if I do: (c-declare "#include <stdio.h>") ((c-lambda () void (string-append "printf(\"%d\\n\"," "10);")) I get: *** ERROR IN "/home/dave/temp/test.scm"@4.11 -- Third argument to 'c-lambda' must be a string Why is that the c-lambda cannot or does not evaluate its arguments? Is this occuring because c-lambda is a macro? I'd like it to evaluate my (string-append ...) because then, I could simplify the usage of the ffi with macros... Thanks! David

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Gambit-list Mars 2008