From: Andy Wingo <wingo@pobox.com>
To: Stefan Israelsson Tampe <stefan.itampe@gmail.com>
Cc: guile-devel@gnu.org
Subject: Re: vhash speed thread safeness
Date: Mon, 24 Mar 2014 21:59:28 +0100 [thread overview]
Message-ID: <87lhvzuxcf.fsf@pobox.com> (raw)
In-Reply-To: <3150759.E8ExfKuC24@warperdoze> (Stefan Israelsson Tampe's message of "Fri, 18 Oct 2013 18:21:04 +0200")
Hi,
Just a late observation :)
On Fri 18 Oct 2013 18:21, Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:
> I did some tests witha C-based vhash implementation, it's possible to
> increse the speed by 30x compared to current vlist imlpementation in
> guile.
If you are using stable-2.0 you are using a bad hash function. Master
has a much better one, though we should still replace it with Siphash or
something soon. Anyway it can be quite a problem for vhashes.
Incidentally, this test case:
(use-modules (ice-9 vlist))
(define vl
(let lp ((n 0))
(if (= n 26)
vlist-null
(vhash-consq (string->symbol
(string (integer->char (+ (char->integer #\a) n))))
n
(lp (1+ n))))))
(let lp ((n 0)) (when (< n #e1e6) (vhash-assq 'j vl) (lp (1+ n))))
takes 1.5s in stable-2.0 and 0.17s in master. The hash function isn't
the only difference of course.
Andy
--
http://wingolog.org/
prev parent reply other threads:[~2014-03-24 20:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-18 16:21 vhash speed thread safeness Stefan Israelsson Tampe
2013-10-29 12:34 ` Ludovic Courtès
2013-10-29 14:21 ` Stefan Israelsson Tampe
2013-10-29 17:54 ` Ludovic Courtès
2013-10-29 18:50 ` Ian Price
2014-03-24 20:59 ` Andy Wingo [this message]
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