From: Simon Wright <simon@pushface.org>
Subject: Re: Problem with -gnatt
Date: 20 Oct 2004 06:19:18 +0100
Date: 2004-10-20T06:19:18+01:00 [thread overview]
Message-ID: <x7vd5zermp5.fsf@smaug.pushface.org> (raw)
In-Reply-To: 4174C40B.8070906@mailinator.com
"Alex R. Mosteo" <devnull@mailinator.com> writes:
> It isn't that contradictory? If locking is costly in a protected
> object, using it for very frequent, very short actions seems
> pointless. It indeed will suggest to use it for rare, longer
> occurrences.
I suppose you need to time it. There's an (x86) hi-res Time package
inthe Booch Components (BC.Support.High_Resolution_Time, see
http://www.pushface.org/components/bc).
For what it's worth, a mutex implemented using a protected type took
about 20 us on a 400 MHz PowerPC under VxWorks ...
> What's a spinlock?
I think it means to loop until a bit becomes clear, then set it (using
an indivisible test-and-set instruction). Doesn't work if you only
have one CPU of course; but if it does work, and the protected regions
are short (a few tens of instructions, depending), will be quicker
than calling some OS sleep() operation.
--
Simon Wright 100% Ada, no bugs.
next prev parent reply other threads:[~2004-10-20 5:19 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-07 10:40 Javadoc-like for Ada Alex R. Mosteo
2004-10-07 11:46 ` stephane richard
2004-10-07 13:05 ` Marc A. Criley
2004-10-07 13:39 ` Alex R. Mosteo
2004-10-07 16:51 ` Problem with -gnatt (was Re: Javadoc-like for Ada) Alex R. Mosteo
2004-10-07 18:43 ` Marc A. Criley
2004-10-07 20:07 ` Björn Persson
2004-10-08 8:40 ` Alex R. Mosteo
2004-10-07 19:21 ` Problem with -gnatt Ludovic Brenta
2004-10-08 8:45 ` Alex R. Mosteo
2004-10-08 9:43 ` Martin Dowie
2004-10-08 13:09 ` Alex R. Mosteo
2004-10-09 14:17 ` Stephen Leake
2004-10-15 20:11 ` Matthew Heaney
2004-10-18 7:59 ` Alex R. Mosteo
2004-10-08 16:52 ` Ludovic Brenta
2004-10-09 14:16 ` Stephen Leake
2004-10-09 14:45 ` Jeff C r e e.m
2004-10-10 12:25 ` Ludovic Brenta
2004-10-10 14:42 ` Stephen Leake
2004-10-15 20:03 ` Matthew Heaney
2004-10-16 13:16 ` Stephen Leake
2004-10-15 20:00 ` Matthew Heaney
2004-10-15 20:06 ` Matthew Heaney
2004-10-18 7:59 ` Alex R. Mosteo
2004-10-18 16:48 ` Matthew Heaney
2004-10-18 18:21 ` Alex R. Mosteo
2004-10-19 0:20 ` Matthew Heaney
2004-10-19 2:41 ` Brian May
2004-10-19 3:08 ` Matthew Heaney
2004-10-19 7:15 ` Alex R. Mosteo
2004-10-19 14:52 ` Matthew Heaney
2004-10-19 15:46 ` Alex R. Mosteo
2004-10-19 20:03 ` Matthew Heaney
2004-10-19 20:38 ` Alex R. Mosteo
2004-10-23 6:28 ` Brian May
2004-10-24 5:45 ` Jeffrey Carter
2004-10-24 8:54 ` Dmitry A. Kazakov
2004-10-20 1:20 ` Jeffrey Carter
2004-10-20 14:48 ` Matthew Heaney
2004-10-19 7:36 ` Alex R. Mosteo
2004-10-20 5:19 ` Simon Wright [this message]
2004-10-20 7:59 ` Alex R. Mosteo
2004-10-11 22:53 ` Javadoc-like for Ada Lionel Draghi
-- strict thread matches above, loose matches on Subject: below --
2004-10-20 1:34 Problem with -gnatt Stephen Leake
2004-10-20 6:37 ` Matthew Heaney
2004-10-20 9:19 ` Pascal Obry
2004-10-20 13:22 Stephen Leake
2004-10-20 15:08 ` Pascal Obry
2004-10-20 16:23 ` Alex R. Mosteo
2004-10-20 16:38 ` Pascal Obry
2004-10-20 20:05 ` Alex R. Mosteo
2004-10-23 20:12 ` Niklas Holsti
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