From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Multitasking and containers
Date: Tue, 28 Nov 2006 09:50:03 +0100
Date: 2006-11-28T09:50:03+01:00 [thread overview]
Message-ID: <zq2w04z5om85.1adxu3bs3a773$.dlg@40tude.net> (raw)
In-Reply-To: uvel0qpmi.fsf@earthlink.net
On Tue, 28 Nov 2006 02:19:55 GMT, Matthew Heaney wrote:
> "Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk> writes:
>
>> Actually, I think Dmitry's view is largely valid in practice, if
>> somewhat extreme.
>
> But we were talking specifically about using a protected object to implement a
> multiple readers schema vs. using a protected object to implement a Hoare-style
> monitor. Because reads must by synchronized, the standard container library
> requires a monitor-style synchronization scheme.
>
> The OP made the argument that this isn't very efficient, and Dmitry responded
> by saying, "well of course systems require custom hand-made solutions." But the
> premise is all wrong, so what Dmitry said is irrelevant. The OP (not Dmitry)
> seems to be confused (he was asking the question, after all) about the
> difference between a mutex and a monitor. He (the OP) probably doesn't
> understand that monitor-type synchronization executes on the current thread, so
> there's no context switch, and so there's no efficiency loss.
I read OP question very differently. He said (let Maciej correct me):
1. That accessing a mutable operation disguised as a protected object's
function were wrong.
2. Using a protected object's procedure/entry would kill concurrency by
serialization of the action to undertake.
Both statements are evidently true.
My comments considered possible solutions *provided* that 2 were really a
problem, because as Jeffrey rightly pointed out, the loss of performance
could be actually minor. But that depends. It is easy to imagine a
situation (massively parallel computing with shared memory) where the loss
could be huge.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2006-11-28 8:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-24 8:51 Multitasking and containers Maciej Sobczak
2006-11-24 10:11 ` Georg Bauhaus
2006-11-24 10:19 ` Dmitry A. Kazakov
2006-11-24 10:35 ` Maciej Sobczak
2006-11-24 11:14 ` Dmitry A. Kazakov
2006-11-24 12:13 ` Matthew Heaney
2006-11-27 4:17 ` Jeffrey R. Carter
2006-11-27 10:30 ` Georg Bauhaus
2006-11-27 18:41 ` Jeffrey R. Carter
2006-11-27 18:57 ` Dmitry A. Kazakov
2006-11-27 19:45 ` Matthew Heaney
2006-11-27 21:15 ` Simon Wright
2006-11-28 1:43 ` Dr. Adrian Wrigley
2006-11-28 2:19 ` Matthew Heaney
2006-11-28 8:50 ` Dmitry A. Kazakov [this message]
2006-11-28 10:31 ` Georg Bauhaus
2006-11-28 11:24 ` Dmitry A. Kazakov
2006-11-29 8:51 ` Georg Bauhaus
2006-11-28 17:12 ` Matthew Heaney
2006-11-28 18:21 ` Dmitry A. Kazakov
2006-11-28 19:17 ` Matthew Heaney
2006-11-29 18:43 ` Dmitry A. Kazakov
2006-11-29 10:14 ` Maciej Sobczak
2006-11-29 15:50 ` Matthew Heaney
2006-11-24 12:12 ` Matthew Heaney
2006-11-24 12:05 ` Matthew Heaney
2006-11-24 12:02 ` Matthew Heaney
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