Gambit-list Février 2009

gambit-list@iro.umontreal.ca

37 participants
66 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

Interactive 3D graphics with Gambit-C
by Alex Sandro Queiroz e Silva 06 Jan '10

06 Jan '10

Hallo, I am thinking about doing some basic 3D graphics with Gambit-C. Although I am sure code generated by Gambit-C is fast enough[1], I am a bit worried about the garbage collector. What's the type of garbage collector used by Gambit? If it kicks in during interactive rendering, should I expect annoying pauses? [1] - http://www.ventonegro.org/2008/09/the-need-for-speed/ -alex http://www.ventonegro.org/

5 7

Re: [gambit-list] Speed improvement of lib/digest.scm
by Marc Feeley 18 Nov '09

18 Nov '09

On 19-Feb-09, at 4:49 PM, Mikael More wrote: > Cool! > > Useful! > > What is the approx speed on your machine btw? > On my 2GHz Mac Book Pro: For MD5: 0.06 seconds per MB. For SHA-1: 0.13 seconds per MB. That's still about 3 times slower than the "md5" utility on my machine, but still not too bad for bit-bashing code entirely written in Scheme. Marc

4 10

scheme on llvm
by lowly coder 31 Jul '09

31 Jul '09

this is kinda off topic, -- but people here seem really smart, so I'll risk the occasional flames for good criticism + insight i think the llvm/jvm projects are really cool, since so much work is put into jitting; and for one reason or another, I like llvm more than jvm i'm curious about the possiblity of a high performance scheme (and perhaps gambit in particular) running on llvm; where the 'initial implementation' may not be all that fast ... but letting llvm jit it away how does this sound? feasible for a scheme (but not gambit)? down the pipes planned for gambit? or totally stupid/crazy? the 'main' advantage of this approach is that I _assume_ that the llvm guys are pretty good at hacking up interpreters / jit's ... so why not benefit from their constant progress :-D

5 7

I/O puzzle...
by Marc Feeley 09 Jui '09

09 Jui '09

Puzzle... what's the bug in the following code? See end of message for answer. (define http-server-start! (lambda (hs stop?) (let ((server-port (open-tcp-server (list port-number: (server-port-number hs) backlog: 128 reuse-address: #t server-address: '#u8(127 0 0 1) ; on localhost interface only char-encoding: 'ISO-8859-1)))) (input-port-timeout-set! server-port 3) (accept-connections hs server-port stop?)))) (define accept-connections (lambda (hs server-port stop?) (let loop () (let ((connection (read server-port))) (if (eof-object? connection) (if (stop?) (close-input-port server-port) (loop)) (begin (if (server-threaded? hs) (let ((dummy-port (open-dummy))) (parameterize ((current-input-port dummy-port) (current-output-port dummy-port)) (thread-start! (make-thread (lambda () (serve-connection hs connection)))))) (serve-connection hs connection)) (loop))))))) . . . . . . . . Answer: the (input-port-timeout-set! server-port 3) is at the wrong place. It sets a timeout ***3 seconds in the future***. So after 3 seconds have passed all calls to read in accept-connections will not block (and lead to a tight, CPU intensive loop). The correct approach is to put the call to (input-port-timeout-set! server-port 3) just before the call to read. Puzzle #2: why did Gambit chose to define timeouts that are not relative to the moment that an I/O function is called? Marc

2 3

gambit introspection
by Jose A. Ortega Ruiz 22 Mar '09

22 Mar '09

hi, i'm working in a scheme-emacs interaction environment providing a subset of the capabilities present in slime. although i'm using guile as the initially supported scheme, the framework is generic on the emacs side and it shouldn't be difficult to add support for other schemes. i'd like to add gambit to the party, but i'm having a hard time finding procedures to obtain metadata about objects living in a running interpreter instance. so far, i've only found ##procedure-locat. in addition, it'd be nice to have: - general location info (the equivalent of ##procedure-locat for macros and variables) - a way of getting all defined bindings starting with a prefix (gsi's REPL does this, but i haven't found how) - a way of getting the arity and parameter names for procedures and macros - a way of getting a procedure's callers and callees - macroexpand: i see there's a family of ##macro-* procedures, but i'm not sure how to use them - metadata associated with namespaces - any other metadata associated with objects that could be used in an inspector although i haven't had the time, i'm sure gambit.el will give me enough clues to interact with the debugger. documentation-wise, my framework knows how to use info docs, so, as long as there're no plans to phase out texinfo as one of gambit's documentation formats, i'm ok on that front too. my apologies if this information is already available somewhere: i'll appreciate it if you send me RTFM with accompanying pointers. thanks a lot for your time. cheers, jao

6 7

Reducing the memory requirements to compile the C files generated by Gambit
by Bradley Lucier 06 Mar '09

06 Mar '09

Marc: The gcc 4.2.* and 4.3.* series compilers have a problem dealing with large "loops" that are "recognized" because of the computed gotos, loops that consist of 50,000+ basic blocks in some instances. This has been "fixed" in the 4.4.* release by attempting loop-invariant-code-motion (LICM) at the register-transfer-language (RTL) level only for loops with fewer than 1,000 block at -O1 and fewer than 10,000 blocks at -O2. Perhaps this change will be backported to the released compiler series, but it hasn't happened yet. Some Linux distributions (e.g., Ubuntu 8.10, Fedora 10) ship 4.3.* or 4.2.* series compilers, and so they have a really hard time compiling some Gambit-generated programs with the default gcc options; e.g., the compiler benchmark takes about 29 GB of memory to compile on x86-64 with the default Gambit gcc options, see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39157 Can you add something to the configure script to see whether gcc-4.[23].* is being used and to add -fno-move-loop-invariants to the gcc options in that case? I added some comments about this to the wiki at http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Configure_script_opti… Brad

3 4

window manager in gambit
by lowly coder 04 Mar '09

04 Mar '09

hey, so my current dev environment is xmonad + emacs + gambit; this is about to become xmonad + jedi + gambit; but I'd prefer to have my window manager be running on gambit too so ... is there anyone else out there also interested in this? we can probably start out with something like scwm or sawmill and hack it to run on gambit ... or if you're really good with x11, we can even start with some thing leaner let me know if there's interest thanks! (mainly interested in this as a hobby project)

7 13

Problem with make check
by Paul Onions 28 Fév '09

28 Fév '09

Hello, When building from the latest GIT sources, running "make check" I get: ------------ TEST 5 (compiler generating C code) rm -f mix.c ../gsc/gsc -:~~bin=../bin,~~lib=../lib,~~include=../include -f -c mix.scm diff test5.ok mix.c 1780c1780 < ___DEF_SUB_FLO(___X17,-0x1L,-0x1L) --- > ___DEF_SUB_FLO(___X17,0x7fffffffL,-0x1L) make[1]: *** [test5] Error 1 make: *** [check] Error 2 I'm running MACOSX 10.5 on a PowerPC machine. Should I be concerned about this? Thanks, Paul

2 2

update?
by Bradley Lucier 27 Fév '09

27 Fév '09

Marc: What? 24 hours without an update? Brad

2 1

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Gambit-list Février 2009