> I
sometimes run two instances
> Neither instance gets slowed down because of cache
> issues.
If you think so, you can continue running two instances. Functionality
available now.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "Qin Liu" <qnliu@xxxxxxcom>
To: <amibroker@xxxxxxxxxps.com>
Sent: Thursday, January 17, 2008 1:48 AM
Subject: [amibroker] Re: Multi CPU anytime soon?
> Hi Tomasz,
>
> Thanks for commenting extensively on this subject.
>
> One thing that will definitely see big gains is to run the different
> cases of an optimization in parallel. I sometimes run two instances
> of AmiBroker on my dual-core processor, each doing its own
> optimization run. Neither instance gets slowed down because of cache
> issues.
>
> Cheers,
> Qin
>
> --- In amibroker@xxxxxxxxxps.com,
"Tomasz Janeczko" <groups@xxx> wrote:
>>
>> Hello,
>>
>> Support for multi-CPU / multi-core is already available in many
> areas mainly related to database handling,
>> for example:
>>
>> - selected real time plugins use multi-threaded processing of data
> (IQFeed plugin, IB plugin)
>> - Indicator Maintenance wizard is multi threaded
>> - some internal operations regardling list view are done in separate
> thread
>> - automatic trading interface (IBController) runs in separate thread
>> - AmiQuote is fully multi-threading program (it can run as much as
> 21 threads at the same time)
>>
>> As far as optimization is considered, it is not multi-threaded right
> now. It is not a matter of
>> "making it MT" but the matter of actually getting speed
advantage.
> You need to understand
>> that things that run on multiple cores are not necesarily faster.
> Actually they can be slower
>> due to cache misses/invalidations/memory access conflicts/context
> switching etc.
>> There are functions (like Foreign) in the AFL that inherently lead
> to data access conflicts when run on more than one CPU/core.
>>
>> I have done *many* benchmarks of various real-world scenarios and my
> findings are that you need
>> to be very careful on what you actually put into multi-threading
> code because you may end up
>> having actually slower result. This is especially the case for tight
> hand coded loops that AFL uses
>> to process arrays. They execute 2 to 3 times faster on single core
> than when same loop is divided
>> into multiple cores. You will start getting 10% advantage only when
> you proceess arrays larger than 100000 bars.
>> This is rare and not really worth effort as it simply bogs down your
> computer and you can hardly move your mouse.
>>
>> So different approaches are tested on real-world data and real-world
> code and I actually measure the time
>> of execution, and will only release any MT addition *IF* speed
> advantage is at least 40% under regular use.
>>
>> Please note that such tests and benchmarking is pretty time
> consuming and I am not giving you any dates.
>> We will see - the work continues.
>>
>> Best regards,
>> Tomasz Janeczko
>> amibroker.com
>> ----- Original Message -----
>> From: "joelamibroker" <joelamibroker@...>
>> To: <amibroker@xxxxxxxxxps.com>
>> Sent: Thursday, August 23, 2007 4:22 PM
>> Subject: [amibroker] Multi CPU anytime soon?
>>
>>
>> > Hi,
>> >
>> > Support for multiple CPUs has been discussed for over a year now.
>> >
>> > Is there any chance that we will be seeing this feature for
> optimisations?
>> >
>> > Joel
>> >
>> >
>> >
>> >
>> > Please note that this group is for discussion between users only.
>> >
>> > To get support from AmiBroker please send an e-mail directly to
>> > SUPPORT {at} amibroker.com
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> >
>> > Yahoo! Groups Links
>> >
>> >
>> >
>> >
>> >
>>
>
>
>
>
> Please note that this group is for discussion between users only.
>
> To get support from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
>
> Yahoo! Groups Links
>
>
>
>
>