Re: Experience with guile + Boehm GC in SND (Re: New versions of rt-compiler.scm, rt-examples.scm and rt.tex

[Kjetil S. Matheussen]

On Mon, 4 Jun 2007, Ludovic Courtès wrote:

> Hi,
>
> "Kjetil S. Matheussen" <address@hidden> writes:
>
> > libgc (v6.8) was compiled with the --enable-threads=posix only.
>
> So `THREAD_LOCAL_ALLOC' was defined in your libgc build, right?

Yes: -DTHREAD_LOCAL_ALLOC=1


> > Running the benchmark program directly in guile gives no
> > difference. Both spent about 50 seconds running the test.
>
> "Directly in Guile" means that you just run:
>
>  $ ./pre-inst-guile gcbench.scm
>
> Is that correct?

I have to compile snd against libguile and its header files, so I have two 
guile installed in two different directories, and set LD_LIBRARY_PATH to 
the right place before running. LD_LIBRARY_PATH is set automatically in
the script that starts snd, and for guile I think you use -rpath? :

ldd -r /usr/bin/guile
        linux-gate.so.1 =>  (0xffffe000)
        libguile.so.17 => /usr/lib/libguile.so.17 (0xb7ed2000)


ldd -r /home/kjetil/site/bin/guile
        linux-gate.so.1 =>  (0xffffe000)
        libguile.so.18 => /home/kjetil/site/lib/libguile.so.18 (0xb7ed8000)
        libgc.so.1 => /home/kjetil/site/lib/libgc.so.1 (0xb7ea8000)




> > Inside snd is another matter:
> >
> >
> >           [1]   [2]      [3]
> > Guile gc  96mb  176mb    54s.
> > Boehm gc  99mb  107mb   118s.
> >
> >
> > [1] Memory before running test reported by top.
> > [2] Memory after running test reported by top
> > [3] Time to run test in seconds.
>
> What does "inside snd" mean exactly?

Snd has its own REPLs which interacts with libguile.


> Is snd multi-threaded?  Does it use `scm_without_guile ()' for instance
> (e.g., when a thread blocks for I/O)?

No, not when snd is being run standalone.


> Does the second run of `gcbench.scm' within Guile alone (no snd) show
> similar performance behavior in the libgc case?  I.e.:
>
>  $ guile-boehm --no-debug
>  guile> (load "gcbench.scm")
>  ;;; takes 50s. to complete
>  guile> (load "gcbench.scm")
>  ;;; takes 118s. to complete

No. But I have ran a series of benchmarks now:


(benchmark 20) in Guile:
Guile: 4.4mb / 277s / 149mb
Boehm: 4.4mb / 243s / 148mb

----

(benchmark 20) in Snd:
Guile: 96mb / 336s / 216mb
Boehm: 99mb / 442s / 257mb [1]

----

(benchmark) (benchmark), in Snd:
Guile: 96mb /  58s / 174mb / 59s / 174mb
Boehm: 99mb / 105s / 108mb / 99s / 116mb

-----

(benchmark) (benchmark), in Guile:
Guile: 4.4mb / 50s / 78mb / 50s / 80mb
Boehm: 5.2mb / 74s / 55mb / 71s / 63mb [2]



[1] Memory usage flipped over from 182.2 to 256.6 right before the 
benchmark was finished.

[2] I ran another time, and got 75s. It seems like my previous result of 
50s might have been ran with the wrong program.





> For libgc, there are a few environment variables that might be
> influential, e.g., `GC_MAXIMUM_HEAP_SIZE' (see `README.environment' from
> libgc).  Likewise for Guile's GC, but they're undocumented AFAIK (grep
> for `scm_getenv_int' in the `libguile' directory).

Any tip about what to try? I did some tweaking with it 7 years ago 
when I ported it to beos and worked on the amigaos port, but haven't 
touched it since.