From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Does Ada tasking profit from multi-core cpus?
Date: Wed, 7 Mar 2007 09:39:43 +0100
Date: 2007-03-07T09:39:43+01:00 [thread overview]
Message-ID: <1lq9zxgrnvfjx$.17ip3w3ei4xdb.dlg@40tude.net> (raw)
In-Reply-To: 0dmdnZIAd76ZpXPYnZ2dnUVZ_uCinZ2d@comcast.com
On Tue, 6 Mar 2007 19:58:31 -0800, Steve wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
> news:rgcukvs1j6ck$.1vjj69zzy1h56$.dlg@40tude.net...
>> On 5 Mar 2007 02:08:22 -0800, Ludovic Brenta wrote:
>>
>>> "� jpluto" wrote:
>>>> Has someone experience with Ada tasking (especially GNAT) on multi-core
>>>> systems?
>>>>
>>>> Show programs with several working tasks a performance boost on
>>>> dual-core or
>>>> quad-core cpus?
>>>
>>> On my dual-core Turion 64 with Debian GNU/Linux and GCC 4.1.2, all is
>>> well. Ada programs using tasking use both cores. I think it would work
>>> on most other platforms too, but YMMV.
>>
>> Apart from using both cores, does anybody know how protected objects
>> function on multi-cores? Especially:
>>
>> 1. Whether protected object's functions are indeed executed concurrently
>> when come from the tasks running on different cores?
>>
>> 2. What are the times required to take/release the protected object's spin
>> lock compared to ones on single core?
>>
>> 3. Can a task switch cores? If yes, what is the overhead of switching?
>
> On Windows, which uses symmetric multiprocessing, I belive two cores works
> the same as two CPU's. With two CPU's the two highest priority threads that
> are in the ready state run concurrently, so yes a task can switch cores.
> Sorry I don't know about the overhead of switching.
> I have run tests on a system with 2 CPU's and found that a single task that
> does a lot of switching winds up using 50% of the CPU time on both CPU's
> (from the task viewer).
Just a side note, the Windows API GetThreadTimes (which the viewer
apparently uses) is corrupted. It counts complete time quants rather than
the performance counter ticks. So, potentially you could observe 1% under
factual 99% CPU load. The bug should appear for threads performing much
synchronization, because they leave the processor before the current quant
expiration.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2007-03-07 8:39 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-29 11:57 Does Ada tasking profit from multi-core cpus? Gerd
2007-01-29 12:04 ` Georg Bauhaus
2007-01-30 13:55 ` Gerd
2007-02-09 10:18 ` karl
2007-02-09 11:03 ` Stefan Lucks
2007-02-09 11:35 ` Ludovic Brenta
2007-03-04 17:54 ` jpluto
2007-03-05 10:08 ` Ludovic Brenta
2007-03-05 13:12 ` Dmitry A. Kazakov
2007-03-06 5:33 ` tmoran
2007-03-06 8:44 ` Dmitry A. Kazakov
2007-03-07 7:52 ` tmoran
2007-03-07 9:31 ` tmoran
2007-03-06 9:40 ` Colin Paul Gloster
2007-03-06 12:47 ` Jeffrey Creem
2007-03-06 14:44 ` Georg Bauhaus
2007-03-06 16:53 ` Dr. Adrian Wrigley
2007-03-06 18:58 ` tmoran
2007-03-07 10:11 ` Colin Paul Gloster
2007-03-07 18:47 ` tmoran
2007-03-06 18:51 ` Jeffrey R. Carter
2007-03-16 14:29 ` Arguments for single-mutex-exclusion on protected types (Was: Does Ada tasking profit from multi-core cpus?) Jacob Sparre Andersen
2007-03-17 5:26 ` Jeffrey R. Carter
2007-03-17 17:22 ` Robert A Duff
2007-03-17 17:52 ` Jeffrey R. Carter
2007-03-17 23:06 ` Randy Brukardt
2007-03-18 17:57 ` Robert A Duff
2007-03-19 21:49 ` Randy Brukardt
2007-03-20 0:55 ` Jeffrey R. Carter
2007-03-20 1:36 ` Randy Brukardt
2007-03-20 16:32 ` Jeffrey R. Carter
2007-03-20 17:51 ` Randy Brukardt
2007-03-21 0:10 ` Jeffrey R. Carter
2007-03-26 23:38 ` Robert A Duff
2007-03-26 23:24 ` Robert A Duff
2007-03-17 10:25 ` Dmitry A. Kazakov
2007-03-18 17:15 ` Arguments for single-mutex-exclusion on protected types Jacob Sparre Andersen
2007-03-18 18:50 ` Dmitry A. Kazakov
2007-03-20 12:38 ` Florian Weimer
2007-03-07 3:58 ` Does Ada tasking profit from multi-core cpus? Steve
2007-03-07 8:39 ` Dmitry A. Kazakov [this message]
2007-03-08 5:21 ` Randy Brukardt
2007-03-08 10:15 ` Dmitry A. Kazakov
2007-03-08 21:18 ` accuracy (was: Does Ada tasking profit from multi-core cpus?) Björn Persson
2007-03-09 8:33 ` accuracy Dmitry A. Kazakov
2007-03-10 1:39 ` accuracy Randy Brukardt
2007-03-10 9:11 ` accuracy Dmitry A. Kazakov
2007-03-11 3:03 ` accuracy Randy Brukardt
2007-03-11 5:21 ` accuracy tmoran
2007-03-11 8:52 ` accuracy Dmitry A. Kazakov
2007-03-11 13:57 ` accuracy Pascal Obry
2007-03-11 14:16 ` accuracy Dmitry A. Kazakov
2007-03-11 14:37 ` accuracy Pascal Obry
2007-03-11 15:50 ` accuracy Dmitry A. Kazakov
2007-03-11 17:38 ` accuracy Pascal Obry
2007-03-11 18:48 ` accuracy Dmitry A. Kazakov
2007-03-12 20:20 ` accuracy Randy Brukardt
2007-03-13 9:33 ` accuracy Dmitry A. Kazakov
2007-03-10 14:53 ` accuracy Stephen Leake
2007-03-10 18:36 ` accuracy Cesar Rabak
2007-03-05 18:46 ` Does Ada tasking profit from multi-core cpus? Jeffrey R. Carter
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