From: "Linus Björnstam" <linus.internet@fastmail.se>
To: "Aleix Conchillo Flaqué" <aconchillo@gmail.com>,
guile-user <guile-user@gnu.org>
Subject: Re: string-for-each vs. for-each+string->list performance
Date: Sun, 07 Jun 2020 13:20:33 +0200 [thread overview]
Message-ID: <5f405299-9249-4357-b6b1-0a81a7e3a033@www.fastmail.com> (raw)
In-Reply-To: <CA+XASoWOno30sV8A3sz1n8w2TNkB+gjikgmXWk+c_2BDJ8iH0A@mail.gmail.com>
Try disassembling it. I suspect the for-each is inlined, and that whatever is going on involves instruction explosion which means you get a lot more optimization opportunities.
That difference seems large though. Try it in guile 2.2 (which shouldnt have the same opportunities for optimization).
--
Linus Björnstam
On Sun, 7 Jun 2020, at 08:27, Aleix Conchillo Flaqué wrote:
> Hi,
>
> in the latest guile-json, 4.1.0. I changed some code to use
> for-each+string->list. The performance seemed nice and I released it.
>
> Christopher Lam pointed out that I could have used string-for-each instead.
> I made the change but the performance degraded a lot:
>
> string-for-each:
>
> scheme@(json parser)> ,t (->bool (scm->json-string json))
> $19 = #t
> ;; 17.909537s real time, 18.063382s run time. 0.207281s spent in GC.
>
> vs
>
> for-each + string->list:
>
> scheme@(json parser)> ,t (->bool (scm->json-string json))
> $20 = #t
> ;; 2.998381s real time, 3.319349s run time. 0.471969s spent in GC.
>
> string-for-each is implemented in scheme here, if Im not wrong:
>
> http://git.savannah.gnu.org/cgit/guile.git/tree/module/rnrs/base.scm#n89
>
> string->list and for-each would use C.
>
> Is that huge gap expected?
>
> This is with Guile 3.0.2.
>
> Best,
>
> Aleix
>
next prev parent reply other threads:[~2020-06-07 11:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-07 6:27 string-for-each vs. for-each+string->list performance Aleix Conchillo Flaqué
2020-06-07 6:33 ` Aleix Conchillo Flaqué
2020-06-07 11:20 ` Linus Björnstam [this message]
2020-06-07 13:50 ` Linus Björnstam
2020-06-12 20:13 ` Ludovic Courtès
2020-06-13 6:41 ` Linus Björnstam
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/guile/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5f405299-9249-4357-b6b1-0a81a7e3a033@www.fastmail.com \
--to=linus.internet@fastmail.se \
--cc=aconchillo@gmail.com \
--cc=guile-user@gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).