From: Dmitry Antipov <dmantipov@yandex.ru>
To: emacs-devel@gnu.org
Subject: Re: Proposal: block-based vector allocator
Date: Mon, 12 Dec 2011 07:07:18 +0400 [thread overview]
Message-ID: <4EE56FE6.4050305@yandex.ru> (raw)
In-Reply-To: <jwvaa71mqnm.fsf-monnier+emacs@gnu.org>
On 12/10/2011 01:04 AM, Stefan Monnier wrote:
> Let us how it turns out.
Results for the byte-compile benchmark, an average of 16 runs:
CPU time spent in user mode, seconds
----< configuration >----< 32bit >----< 64bit >----
default, stack mark 74.07 84.87
default, GCPROs 72.90 81.37
patched, stack mark 71.35 81.57
patched, GCPROs 70.16 82.18
Peak heap utilization, KBytes
----< configuration >----< 32bit >----< 64bit >----
default, stack mark 41499 73651
default, GCPROs 37918 65648
patched, stack mark 38310 67169
patched, GCPROs 38052 65730
Total time spent in GC, seconds
----< configuration >----< 32bit >----< 64bit >----
default, stack mark 23.58 32.32
default, GCPROs 21.94 30.43
patched, stack mark 21.64 29.89
patched, GCPROs 21.13 29.22
Average time per GC, milliseconds
----< configuration >----< 32bit >----< 64bit >----
default, stack mark 27.62 36.03
default, GCPROs 25.57 33.93
patched, stack mark 25.22 33.34
patched, GCPROs 24.63 32.57
First of all, I was surprised with such a difference between 32- and
64-bit code. Due to this, I'm wondering whether --with-wide-int makes
sense: I expect it to be "too fat, too bloated" for a 32-bit CPU
(but would be glad to mistake).
Next, block vector allocation makes GC a bit faster. I expected it,
and can explain this effect with the better locality of vector-like
objects, which takes a good care of sweeping.
Finally, I'm pretty sure that block vector allocation makes a
very negligible effect for the case of GCPROs. In terms of peak
heap utilization, it's 0.35% worse on 32-bit and just 0.12% worse
on 64-bit. In terms of CPU usage, results are more interesting:
1% worse for 64-bit case, but 3.8% better for 32-bit. The only
explanation I have for this effect is that an arithmetic used in
splitting/coalescing operations creates some pressure on the CPU
in 64-bit mode, but 32-bit version of the same code may be implicitly
executed in parallel by the 64-bit core. Due to this, I don't consider
my 32-bit benchmark as fairly representative - it should be done
on a real 32-bit core and not in 'compatibility mode' on 64-bit one.
Dmitry
next prev parent reply other threads:[~2011-12-12 3:07 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
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 [this message]
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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