Gambit-list Juillet 2007

gambit-list@iro.umontreal.ca

14 participants
16 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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Gambit installers
by Marc Feeley 03 Aoû '07

03 Aoû '07

Does anyone have experience creating installers for Windows and MacOS X? What are the best free installers? Marc

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Is there a way to adjust serial port settings?
by Terry Parks 30 Jul '07

30 Jul '07

Also is there a way to search the list archives? Terry Parks

3 3

Valid namespace prefix
by James Long 30 Jul '07

30 Jul '07

How come Gambit enforces the module# syntax for namespaces? I have just started using them, and have looked at many posts describing the system, but I don't remember anyone explaining the reason for this syntax. For example, trying anything different than module gives an error: > (namespace ("foo:")) *** ERROR IN (console)(a)1.13 -- Ill-formed namespace prefix I would like to use the colon syntax as I find it much more readable, especially for user-land code. I'm going to usually use fully qualified names, so this slight readability improvement is important. Is there a reason I shouldn't be able to do this?

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Using the tcc compiler
by Christian Jaeger 28 Jul '07

28 Jul '07

Hello I've just discovered that tcc¹ is able to compile the C code generated by Gambit. In simple cases the compiled object files work just flawlessly (albeit ~3 times slower than when compiled with gcc in a fixnum-loop microbenchmark, but that's ok). When I compile one of my bigger modules (which takes 3 seconds for compilation from Scheme to C and 17 seconds to compile from C to binary with gcc 4.1.2, and only 1 second to compile from C to binary with tcc 0.9.23), it's doing wrong calculations (I'm doing signal processing, with tcc it just outputs zeroes all the time). The way I've used tcc in the above tests was by just linking tcc into the PATH as gcc (mkdir ~/bin; ln -s /usr/bin/tcc ~/bin/gcc; PATH="~/bin:$PATH"; start gsc interactively and use compile-file (through chjmodule) as usual). Should I take a different approach? Or should I start debugging problems / send bug reports with code when compiled with tcc? Having 5 times faster compile times would help development in those cases where using the interpreter isn't possible (because it is too slow or because the modules are including FFI code), albeit it's not a high priority. (Alternatively I might possibly speed up gcc by not using single-host and no -O flag. How can I achieve those settings from inside gsc (when using |compile-file|), btw?) Christian. ¹http://fabrice.bellard.free.fr/tcc/

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Possible gc bug?
by Bradley Lucier 26 Jul '07

26 Jul '07

Marc: I've got a vector of length 262,144, each element of which is supposed to be a length 4 f64vector. Well, I get a interrupt in my program when it hits one of these elements that is only of length 2. Further investigation shows that only two elements of the whole vector have length 2: > 1> (Array-for-each (lambda (p) (if (not (= (f64vector-length p) 4)) > (pp p))) p) > #f64(-.7079566418808501 -.2467907960478973) > #f64(-.6672517342403924 -.31362141535348953) This presents a very interesting debugging problem. Eventually, I changed the code storing an array to check whether all the f64vectors are the same length when the Array is built: > (set! make-Array-base > (lambda (domain ;; an Interval > getter ;; (lambda (i_0 ... i_n-1) ...) > returns a value for (i_0,...,i_n-1) in (Array-domain a) > ;; Part of mutable arrays > setter ;; (lambda (v i_0 ... i_n-1) ...) > sets a value for (i_0,...,i_n-1) in (Array-domain a) > ;; Part of Fixed arrays > manipulators ;; a Fixed-array-manipulator > body ;; the backing store for this array > indexer ;; see below > affine ;; A list that says in which > coordiantes the indexer is affine. > safe? ;; do we check whether bounds (in > getters and setters) and values (in setters) are valid > ) > (if (and body > (vector? body) > (< 0 (vector-length body)) > (let ((element (vector-ref body 0))) > (and (f64vector? element) > (let ((l (f64vector-length element))) > (not (every (lambda (p) (= (f64vector-length p) l)) (vector- > >list body))))))) > (error "Bzzt, thank you for playing") > (original-make-Array-base domain ;; an Interval > getter ;; (lambda (i_0 ... i_n-1) ...) > returns a value for (i_0,...,i_n-1) in (Array-domain a) > ;; Part of mutable arrays > setter ;; (lambda (v i_0 ... i_n-1) ...) > sets a value for (i_0,...,i_n-1) in (Array-domain a) > ;; Part of Fixed arrays > manipulators ;; a Fixed-array-manipulator > body ;; the backing store for this array > indexer ;; see below > affine ;; A list that says in which > coordiantes the indexer is affine. > safe? ;; do we check whether bounds (in > getters and setters) and values (in setters) are valid > )))) and everything passed. The code works and is exercised: > 1> (make-Array-base #f #f #f #f (vector '#f64(0.0) '#f64(0. 0.)) #f > #f #f) > *** ERROR IN (console)(a)8.1 -- Bzzt, thank you for playing I'm only human, so I want to blame the system rather than my own code. It makes me wonder whether there is still a gc bug in beta 22, whether that bug has been fixed for the upcoming beta 23, etc. Any suggestions? Brad

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System Type
by Jeremie Lasalle Ratelle 25 Jul '07

25 Jul '07

Is there a way to get the host system type at runtime in Gambit-C? ex. i686-pc-linux-gnu

2 1

Compiling gsc .exe unWindows with MSYS
by David Rush 21 Jul '07

21 Jul '07

Hey there, I'm planning to upgrade to the most recent G4 on Windows, but I dont; imagine it will make a huge difference with this. I'm a little stumped by the following link-time errors I am getting using MSYS (and hence, I believe the MinGW version of gcc) to compile and link: >\tools\gambit-c\4.0b20\bin\gsc -verbose -debug -link test.scm >gcc -I /tools/gambit-c/4.0b20/include test.c test_.c -L /tools/gambit-c/4.0b20/lib gcc -I /tools/gambit-c/4.0b20/include test.c test_.c -L /tools/gambit-c/4.0b20/lib C:\DOCUME~1\drr\LOCALS~1\Temp/ccsPaaaa.o(.text+0x6b):test.c: undefined reference to `___gstate' C:\DOCUME~1\drr\LOCALS~1\Temp/ccsPaaaa.o(.text+0xb3):test.c: undefined reference to `___gstate' C:\DOCUME~1\drr\LOCALS~1\Temp/ccsPaaaa.o(.text+0x124):test.c: undefined reference to `___gstate' C:\DOCUME~1\drr\LOCALS~1\Temp/ccsPaaaa.o(.text+0x150):test.c: undefined reference to `___gstate' C:\DOCUME~1\drr\LOCALS~1\Temp/ccsPaaaa.o(.text+0x1be):test.c: undefined reference to `___gstate' c:/tools/msys/1.0/bin/../lib/gcc-lib/mingw32/3.2.3/../../../libmingw32.a(main.o)(.text+0x97):main.c: undefined reference to `WinMain@16' david -- Once you label me, you negate me - Soren Kierkegaard

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Gambit-list Juillet 2007