Gambit-list Janvier 2008

gambit-list@iro.umontreal.ca

20 participants
24 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

2 2

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

3 6

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

3 10

Re: [gambit-list] Gambit and termite on an embedded system (Nintendo DS)?
by Raoul Duke 06 Fév '08

06 Fév '08

hi, I'm curious to know how folks have fared in attempting to get things onto sundry embedded systems. E.g there are inexpensive-but-limited things like the Parallax Propeller which would be possibly neat to program via something like Termite. thanks for any news.

6 12

AWS, Termite, and Snow
by Joe Hosteny 03 Fév '08

03 Fév '08

Hi all, First of all, let me preface this email with a disclaimer. I'm fairly new (again) to Scheme (last exposure was 10+ years ago in college). I'm still feeling my way around a bit, and have settled on Gambit, Chicken, and PLT, to a lesser extent. What I'm trying to say is - dumb questions may follow! I recently wrote a library to manage a cluster of machines in Amazon's EC2. I'm looking to totally rewrite it, and port it to Scheme in the process. I was also looking at having some facility for managing the cluster from within, with event monitoring via SQS or Termite. Currently, the library does that via polling from a machine external to the cluster. It's not ideal, but was sufficient to get my application working. As a start, I wrote a simple Snow package to do MD5 and SHA1 HMAC calculations (the AWS query string API uses SHA1 signatures). I started to look around for some utilities for URI parsing and encoding for use in Gambit, but didn't seem to find anything. So, first question - is anyone aware of a suitable package for this? Second question - if one doesn't exist, what do people do for regular expression parsing in Gambit? Since I haven't really fleshed out the new architecture, I'm not sure it's a requirement that I host code to both communicate events across the cluster and issue AWS API calls from within the same executable. So I guess an option would be to use Chicken for the HTTP stuff, and Gambit for Termite and making calls to the code written with Chicken (though at that point, it may make sense to just use one of the Ruby or Java libs for that part). I'd prefer not to, if for nothing more than to be able to contribute the AWS portion as a Chicken or Snow package. So, a few general questions follow. From recent mailing list discussions, it sounds like Termite will be targeted towards Gambit only, for the time being at least. Guillaume, is that correct? If not, do you have an idea of when it might be seen on other Schemes (specifically, Chicken or PLT)? Also, does anyone have a feel for what is going on with Snow? It seems like the traffic on the mailing list is a bit slow, and the number of packages is still relatively few. Don't get me wrong - my preference would be to contribute any work back as Snow packages, if at all feasible. That goes for lower level support packages as well, provided that I could find some collaborators. I also intend on making an AMI available with Gambit, Termite and any of the packages I produce pre-installed. Cheers, --Joe www.maraudingrobots.com

6 12

Threads blocking and IO
by François Magnan 31 Jan '08

31 Jan '08

Hello, I am experiencing a strange bug in my code that would be long to explain. To resume the context, I have many threads running in parallel, some open-process IO, some tcp-server IO and some termite processes. At some point all the threads become blocked indefinitely and the program sleeps forever. I stumbled on the following paragraph in the threads section of the Gambit doc: ``A thread is blocked if it is waiting for a mutex to become unlocked, an I/O operation to become possible, the end of a “sleep” period, etc. '' I think this may lead me to a solution to my bug but I don't clearly understand the statement. Could there be an IO operation that blocks all my threads? Any help would be greatly appreciated. Thank you, Francois Magnan

5 5

direction of a tcp object port?
by Bob McIsaac 29 Jan '08

29 Jan '08

Hi: How does one alter the directionality of a tcp object port? It defaults to input-port which results in an exception for a write form. -Bob (define *server-port* 5603) (define (start-tcp) (define sp (open-tcp-server (list port-number: *server-port* ;;direction: input-output ))) ;;(port-settings-set! (list direction: 'input-output)) (if (port? sp) (display "is-a-port\n") (display "not-a-port\n")) (if (input-port? sp) (display "is-a-input-port\n")) (if (output-port? sp) (display "is-a-output-port\n")) sp)

2 3

FYI: Scheme procedure for Watcom
by Bob McIsaac 27 Jan '08

27 Jan '08

Hi: http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Watcom_Makefile_Proce… (written in Scheme) creates an OpenWatcom makefile that has rules for a static library. An example at the bottom of the page shows how to link everything for application.exe As stated in Gambit docs, Watcom is slower than GCC. However, one can still devel with Watcom and tinker with that quirky Msys-mingw only if optimization is necessary at the end of a project. Cheers, -Bob-

1 0

error running with emacs in windows xp
by Aaron Ash 26 Jan '08

26 Jan '08

Hello, When running gambit 4.0b22 (or termite) with and without --enable-gcc-opts compiled in I get an error when I press C-d in the debugger. Here is an interaction log in the emacs *scheme* buffer: Gambit Version 4.0 beta 22 > (wtf) *** ERROR IN (stdin)(a)1.2 -- Unbound variable: wtf ;;;; Note: I press C-d when the first debug prompt appears and this error is raised. 1> *** ERROR IN (stdin)(a)1.2 -- The pipe has been ended. (peek-char '#<input-port #2 (stdin)>) 1> *** ERROR IN (stdin)(a)1.2 -- The pipe has been ended. (peek-char '#<input-port #2 (stdin)>) 1> *** ERROR IN (stdin)(a)1.2 -- The pipe has been ended. (peek-char '#<input-port #2 (stdin)>) 1> *** ERROR IN (stdin)(a)1.2 -- The pipe has been ended. (peek-char '#<input-port #2 (stdin)>) The error keeps looping until I kill the gsi.exe process with the task manager. Any ideas what's going on here? The debug commands still seem to work fine though. ie. ,t ,d etc.

2 1

Latest sources don't build on RHEL 4.2
by Bradley Lucier 26 Jan '08

26 Jan '08

The expanded sources for os_io.c on RHEL 4.2 show > # 23 "/usr/include/bits/sigset.h" 3 4 > typedef int __sig_atomic_t; > > > > > typedef struct > { > unsigned long int __val[(1024 / (8 * sizeof (unsigned long > int)))]; > } __sigset_t; then > # 35 "/usr/include/sys/select.h" 2 3 4 > > > > typedef __sigset_t sigset_t; then > # 5958 "os_io.c" > typedef sigset_t sigset_type; > > > > > static sigset_type block_signal > (int signum) > > > { > sigset_type oldmask = 0; > > > > sigset_type toblock; > > sigemptyset (&toblock); > sigaddset (&toblock, signum); > sigprocmask (0, &toblock, &oldmask); > # 5986 "os_io.c" > return oldmask; > } and gcc rightly complains: > gcc -I../include -I. -Wall -W -Wno-unused -O1 -fno-math-errno - > fschedule-insns2 -fno-trapping-math -fno-strict-aliasing -fwrapv - > fomit-frame-pointer -fPIC -fno-common -mieee-fp -save-temps - > DHAVE_CONFIG_H -D___PRIMAL -D___LIBRARY -D___GAMBCDIR="\"/pkgs/ > Gambit-C//v4.1.2\"" -D___SYS_TYPE_CPU="\"x86_64\"" - > D___SYS_TYPE_VENDOR="\"unknown\"" -D___SYS_TYPE_OS="\"linux-gnu\"" - > c os_io.c > os_io.c: In function â: > os_io.c:5968: error: invalid initializer So I suggest you change os_io.c from > ___HIDDEN sigset_type block_signal > ___P((int signum), > (signum) > int signum;) > { > sigset_type oldmask = 0; to > ___HIDDEN sigset_type block_signal > ___P((int signum), > (signum) > int signum;) > { > sigset_type oldmask; Brad

2 1

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Gambit-list Janvier 2008