Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

[Ludovic Courtès]

Hello,

"Andy Wingo" <wingo@pobox.com> skribis:

> commit 79eb47ea47650ef42c545931726277a7118a0210
> Author: Andy Wingo <wingo@pobox.com>
> Date:   Fri Feb 24 23:05:02 2012 +0100
>
>     port i/o optimizations for iso-8859-1
>     
>     * libguile/ports.h (scm_t_port_encoding_mode):
>     * libguile/ports.c (scm_c_make_port_with_encoding):
>       (scm_i_set_port_encoding_x): Add special treatment for latin1
>       encoding.
>       (get_latin1_codepoint, get_codepoint): Add latin1 fast-path.
>     
>     * libguile/print.c (display_string_as_latin1): Add latin1 fastpath.

The problems with fast paths is that they become less fast when there
are many of them.

How does this change influence ‘benchmark-suite/benchmarks/ports.bm’?

Also, how important is it to treat Latin-1 specially?  I can see that
UTF-8 is important, because it’s ubiquitous and a Unicode encoding, but
Latin-1...

More importantly, there’s code duplication.

> +/* Read an ISO-8859-1 codepoint (a byte) from PORT.  On success, return
> +   *0 and set CODEPOINT to the codepoint that was read, fill BUF with
> +   *its UTF-8 representation, and set *LEN to the length in bytes.
> +   *Return `EILSEQ' on error.  */

ESTARS

Thanks,
Ludo’.

Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

[Andy Wingo]

Hi!

On Sun 26 Feb 2012 22:38, ludo@gnu.org (Ludovic Courtès) writes:

> "Andy Wingo" <wingo@pobox.com> skribis:
>
>> commit 79eb47ea47650ef42c545931726277a7118a0210
>> Author: Andy Wingo <wingo@pobox.com>
>> Date:   Fri Feb 24 23:05:02 2012 +0100
>>
>>     port i/o optimizations for iso-8859-1
>>     
> The problems with fast paths is that they become less fast when there
> are many of them.
>
> How does this change influence ‘benchmark-suite/benchmarks/ports.bm’?

Dunno, that wasn't my benchmark.  It makes the web server go faster
(e.g. guile examples/web/debug-sxml.scm).

The reason it makes sense to optimize for this encoding is because it's
our narrow encoding.  If we switch to utf-8 internally (for example),
this path doesn't make sense any more.

>> +/* Read an ISO-8859-1 codepoint (a byte) from PORT.  On success, return
>> +   *0 and set CODEPOINT to the codepoint that was read, fill BUF with
>> +   *its UTF-8 representation, and set *LEN to the length in bytes.
>> +   *Return `EILSEQ' on error.  */
>
> ESTARS

:)  Will fix.

Andy
-- 
http://wingolog.org/

Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

[Ludovic Courtès]

Hi,

Andy Wingo <wingo@pobox.com> skribis:

> On Sun 26 Feb 2012 22:38, ludo@gnu.org (Ludovic Courtès) writes:
>
>> "Andy Wingo" <wingo@pobox.com> skribis:
>>
>>> commit 79eb47ea47650ef42c545931726277a7118a0210
>>> Author: Andy Wingo <wingo@pobox.com>
>>> Date:   Fri Feb 24 23:05:02 2012 +0100
>>>
>>>     port i/o optimizations for iso-8859-1
>>>     
>> The problems with fast paths is that they become less fast when there
>> are many of them.
>>
>> How does this change influence ‘benchmark-suite/benchmarks/ports.bm’?
>
> Dunno, that wasn't my benchmark.  It makes the web server go faster
> (e.g. guile examples/web/debug-sxml.scm).

Can you check with that benchmark?  I think it’s important to have
concrete figures when doing such a change, to make sure the
performance/maintenance cost ratio is good.

> The reason it makes sense to optimize for this encoding is because it's
> our narrow encoding.

I don’t see how Guile’s internal representation is relevant here, since
we’re talking about input/output.

UTF-8 is used very widely out there, and that’s why I’d consider it
important to have fast UTF-8 I/O.  The same cannot be said of Latin-1.

Thanks,
Ludo’.

Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

[Andy Wingo]

Hi!

On Mon 27 Feb 2012 16:57, ludo@gnu.org (Ludovic Courtès) writes:

>>> How does this change influence ‘benchmark-suite/benchmarks/ports.bm’?
>>
>> Dunno, that wasn't my benchmark.  It makes the web server go faster
>> (e.g. guile examples/web/debug-sxml.scm).
>
> Can you check with that benchmark?  I think it’s important to have
> concrete figures when doing such a change, to make sure the
> performance/maintenance cost ratio is good.

Before:

    wingo@badger:~/src/guile-master$ ./benchmark-guile ports.bm
    Benchmarking /home/wingo/src/guile-master/meta/guile ... ports.bm
    with GUILE_LOAD_PATH=/home/wingo/src/guile-master/benchmark-suite
    ;; running guile version 2.1.0.43-4813a-dirty
    ;; calibrating the benchmarking framework...
    ;; framework time per iteration: 3.81469669342041e-8
    ("ports.bm: peek-char: latin-1 port" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
    ("ports.bm: peek-char: utf-8 port, ascii character" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
    ("ports.bm: peek-char: utf-8 port, Korean character" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
    ("ports.bm: read-char: latin-1 port" 10000000 user 0.7 benchmark 0.318530330657959 bench/interp 0.318530330657959 gc 0.0)
    ("ports.bm: read-char: utf-8 port, ascii character" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
    ("ports.bm: read-char: utf-8 port, Korean character" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
    ("ports.bm: char-ready?: latin-1 port" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
    ("ports.bm: char-ready?: utf-8 port, ascii character" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
    ("ports.bm: char-ready?: utf-8 port, Korean character" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
    ("ports.bm: rdelim: read-line" 1000 user 0.38 benchmark 0.379961853033066 bench/interp 0.297933677033066 gc 0.082028176)

After:

    ;; running guile version 2.1.0.43-4813a-dirty
    ;; calibrating the benchmarking framework...
    ;; framework time per iteration: 3.81469669342041e-8
    ("ports.bm: peek-char: latin-1 port" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
    ("ports.bm: peek-char: utf-8 port, ascii character" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
    ("ports.bm: peek-char: utf-8 port, Korean character" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
    ("ports.bm: read-char: latin-1 port" 10000000 user 0.74 benchmark 0.358530330657959 bench/interp 0.358530330657959 gc 0.0)
    ("ports.bm: read-char: utf-8 port, ascii character" 10000000 user 0.76 benchmark 0.378530330657959 bench/interp 0.378530330657959 gc 0.0)
    ("ports.bm: read-char: utf-8 port, Korean character" 10000000 user 0.77 benchmark 0.388530330657959 bench/interp 0.388530330657959 gc 0.0)
    ("ports.bm: char-ready?: latin-1 port" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
    ("ports.bm: char-ready?: utf-8 port, ascii character" 10000000 user 0.64 benchmark 0.258530330657959 bench/interp 0.258530330657959 gc 0.0)
    ("ports.bm: char-ready?: utf-8 port, Korean character" 10000000 user 0.62 benchmark 0.238530330657959 bench/interp 0.238530330657959 gc 0.0)
    ("ports.bm: rdelim: read-line" 1000 user 0.39 benchmark 0.389961853033066 bench/interp 0.306389294033066 gc 0.083572559)

The times are quite variable, though.

Regards,

Andy
-- 
http://wingolog.org/

Re: [Guile-commits] GNU Guile branch, master, updated. v2.1.0-68-g79eb47e

[Ludovic Courtès]

Hi,

Andy Wingo <wingo@pobox.com> skribis:

> Hi!
>
> On Mon 27 Feb 2012 16:57, ludo@gnu.org (Ludovic Courtès) writes:
>
>>>> How does this change influence ‘benchmark-suite/benchmarks/ports.bm’?
>>>
>>> Dunno, that wasn't my benchmark.  It makes the web server go faster
>>> (e.g. guile examples/web/debug-sxml.scm).
>>
>> Can you check with that benchmark?  I think it’s important to have
>> concrete figures when doing such a change, to make sure the
>> performance/maintenance cost ratio is good.
>
> Before:
>
>     wingo@badger:~/src/guile-master$ ./benchmark-guile ports.bm
>     Benchmarking /home/wingo/src/guile-master/meta/guile ... ports.bm
>     with GUILE_LOAD_PATH=/home/wingo/src/guile-master/benchmark-suite
>     ;; running guile version 2.1.0.43-4813a-dirty
>     ;; calibrating the benchmarking framework...
>     ;; framework time per iteration: 3.81469669342041e-8
>     ("ports.bm: peek-char: latin-1 port" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
>     ("ports.bm: peek-char: utf-8 port, ascii character" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
>     ("ports.bm: peek-char: utf-8 port, Korean character" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
>     ("ports.bm: read-char: latin-1 port" 10000000 user 0.7 benchmark 0.318530330657959 bench/interp 0.318530330657959 gc 0.0)
>     ("ports.bm: read-char: utf-8 port, ascii character" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
>     ("ports.bm: read-char: utf-8 port, Korean character" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
>     ("ports.bm: char-ready?: latin-1 port" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
>     ("ports.bm: char-ready?: utf-8 port, ascii character" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
>     ("ports.bm: char-ready?: utf-8 port, Korean character" 10000000 user 0.57 benchmark 0.188530330657959 bench/interp 0.188530330657959 gc 0.0)
>     ("ports.bm: rdelim: read-line" 1000 user 0.38 benchmark 0.379961853033066 bench/interp 0.297933677033066 gc 0.082028176)
>
> After:
>
>     ;; running guile version 2.1.0.43-4813a-dirty
>     ;; calibrating the benchmarking framework...
>     ;; framework time per iteration: 3.81469669342041e-8
>     ("ports.bm: peek-char: latin-1 port" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
>     ("ports.bm: peek-char: utf-8 port, ascii character" 700000 user 0.05 benchmark 0.0232971231460571 bench/interp 0.0232971231460571 gc 0.0)
>     ("ports.bm: peek-char: utf-8 port, Korean character" 700000 user 0.08 benchmark 0.0532971231460571 bench/interp 0.0532971231460571 gc 0.0)
>     ("ports.bm: read-char: latin-1 port" 10000000 user 0.74 benchmark 0.358530330657959 bench/interp 0.358530330657959 gc 0.0)
>     ("ports.bm: read-char: utf-8 port, ascii character" 10000000 user 0.76 benchmark 0.378530330657959 bench/interp 0.378530330657959 gc 0.0)
>     ("ports.bm: read-char: utf-8 port, Korean character" 10000000 user 0.77 benchmark 0.388530330657959 bench/interp 0.388530330657959 gc 0.0)
>     ("ports.bm: char-ready?: latin-1 port" 10000000 user 0.68 benchmark 0.298530330657959 bench/interp 0.298530330657959 gc 0.0)
>     ("ports.bm: char-ready?: utf-8 port, ascii character" 10000000 user 0.64 benchmark 0.258530330657959 bench/interp 0.258530330657959 gc 0.0)
>     ("ports.bm: char-ready?: utf-8 port, Korean character" 10000000 user 0.62 benchmark 0.238530330657959 bench/interp 0.238530330657959 gc 0.0)
>     ("ports.bm: rdelim: read-line" 1000 user 0.39 benchmark 0.389961853033066 bench/interp 0.306389294033066 gc 0.083572559)
>
> The times are quite variable, though.

Thanks for running the bench!  That’s not very conclusive, though.

I improved ports.bm in stable-2.0 (in particular, the ‘read-char’
benchmarks made little sense before as they quickly reached EOF).  It
would be ideal if you could try it, and use --iteration-factor to have
longer timings.

Thanks,
Ludo’.