From: Stefan Monnier <monnier@IRO.UMontreal.CA>
To: Dmitry Antipov <dmantipov@yandex.ru>
Cc: emacs-devel@gnu.org
Subject: Re: Proposal: block-based vector allocator
Date: Thu, 08 Dec 2011 08:52:57 -0500 [thread overview]
Message-ID: <jwvpqfzw56m.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <4EE07A53.3060204@yandex.ru> (Dmitry Antipov's message of "Thu, 08 Dec 2011 12:50:27 +0400")
>> I'm not convinced your result is because your code does better than
>> malloc. Instead I expect it's because it avoids the mem_node overhead.
>> Recompiling and trying again without conservative stack scanning should
>> factor out this effect.
> Without conservative stack scanning, it works at least not worse
> (I believe we should ignore the differences less than, say, 0.5%).
Sounds about right (performance of vector allocation, both in terms of
memory and CPU use, should be lost in the noise unless the allocator
really suffers from a serious problem, as is the case with the current
allocator because of the mem_node allocated alongside).
> But, as I have said, there are further improvements possible.
I think the improvements should focus on simplicity since I doubt we can
get measurably much better.
>> You can't do compaction without changing the Lisp_Vector's layout
>> (adding an indirection, as is done for Lisp_Strings).
> I know, and I'm just saying that my proposal contains nothing which
> makes compaction impossible or too tricky.
OK.
>> I thought we agreed that GC performance is not a concern here.
>> Of course, every change to the layout can impact the performance of the
>> GC. Have you measured the impact of your code on GC performance?
> Not yet. But will do it, of course.
I wouldn't bother.
BTW:
I'm still curious why you have a "order608" for 4KB blocks, since
dividing the 4KB block into 608 would leave you with a lot of padding at
the end and reducing the number of distinct "orders" should
reduce fragmentation.
Stefan
next prev parent reply other threads:[~2011-12-08 13:52 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-06 5:22 Proposal: block-based vector allocator Dmitry Antipov
2011-12-06 13:35 ` Stefan Monnier
2011-12-06 15:14 ` Dmitry Antipov
2011-12-06 19:39 ` Stefan Monnier
2011-12-07 5:05 ` Dmitry Antipov
2011-12-07 12:27 ` Carsten Mattner
2011-12-07 13:52 ` Stefan Monnier
2011-12-07 16:08 ` Dmitry Antipov
2011-12-07 16:30 ` Stefan Monnier
2011-12-08 8:50 ` Dmitry Antipov
2011-12-08 13:52 ` Stefan Monnier [this message]
2011-12-08 1:53 ` Stephen J. Turnbull
2011-12-08 4:41 ` Dmitry Antipov
2011-12-08 14:10 ` Stefan Monnier
2011-12-08 16:48 ` Dmitry Antipov
2011-12-08 19:58 ` Stefan Monnier
2011-12-09 7:32 ` Eli Zaretskii
2011-12-09 9:04 ` Dmitry Antipov
2011-12-09 14:05 ` Stefan Monnier
2011-12-09 16:15 ` Dmitry Antipov
2011-12-09 21:04 ` Stefan Monnier
2011-12-11 13:18 ` Dmitry Antipov
2011-12-12 3:07 ` Dmitry Antipov
2011-12-12 16:24 ` Stefan Monnier
2011-12-09 4:44 ` Stephen J. Turnbull
[not found] ` <jwvaa1yjs21.fsf-monnier+emacs@gnu.org>
2012-05-17 7:58 ` Dmitry Antipov
2012-05-18 17:40 ` Stefan Monnier
2012-05-21 12:19 ` Dmitry Antipov
2012-05-21 13:02 ` Andreas Schwab
2012-05-21 13:48 ` Dmitry Antipov
2012-05-21 15:07 ` Andreas Schwab
2012-05-22 5:23 ` Ken Raeburn
2012-05-21 20:12 ` Stefan Monnier
2012-05-22 8:24 ` Dmitry Antipov
2012-05-31 13:44 ` Dmitry Antipov
2012-05-31 15:43 ` Paul Eggert
2012-06-01 5:15 ` Dmitry Antipov
2012-06-01 5:44 ` Paul Eggert
2012-06-01 9:06 ` Dmitry Antipov
2012-06-01 17:36 ` Stefan Monnier
2012-06-02 0:32 ` Paul Eggert
2012-06-02 7:41 ` Eli Zaretskii
2012-06-03 6:49 ` Paul Eggert
2012-06-03 14:26 ` Eli Zaretskii
2012-05-31 21:16 ` Stefan Monnier
2012-06-01 7:34 ` Dmitry Antipov
2012-06-01 17:40 ` Stefan Monnier
2012-06-01 17:43 ` Stefan Monnier
2012-06-06 7:02 ` Dmitry Antipov
2012-06-06 13:13 ` Stefan Monnier
2012-06-06 14:58 ` Dmitry Antipov
2012-06-06 19:18 ` Stefan Monnier
2012-06-07 10:03 ` Dmitry Antipov
2012-06-07 14:07 ` Stefan Monnier
2012-06-08 5:50 ` Dmitry Antipov
2012-06-08 6:17 ` Stefan Monnier
2012-06-08 8:49 ` Dmitry Antipov
2012-06-08 8:53 ` Eli Zaretskii
2012-06-08 9:41 ` Eli Zaretskii
2012-06-08 10:00 ` Eli Zaretskii
2012-06-08 6:57 ` Eli Zaretskii
2012-06-08 6:38 ` Paul Eggert
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