From:
amibroker@xxxxxxxxxxxxxxx [mailto:amibroker@xxxxxxxxxxxxxxx] On Behalf Of Steve Dugas
Sent: Thursday, June 23, 2005 2:56
PM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: [amibroker] AmiBroker
Performance Continued -- What Settings are Fastest?
----- Original Message -----
Sent: Thursday, June 23,
2005 10:51 AM
Subject: RE: [amibroker]
AmiBroker Performance Continued -- What Settings are Fastest?
Tomasz,
Is TC2005 considered a “slow”
plugin?
Regards,
Dan.
From: amibroker@xxxxxxxxxxxxxxx
[mailto:amibroker@xxxxxxxxxxxxxxx] On Behalf
Of Tomasz Janeczko
Sent: Thursday, June 23, 2005 6:50
AM
To: amibroker@xxxxxxxxxxxxxxx
Subject: Re: [amibroker] AmiBroker
Performance Continued -- What Settings are Fastest?
Hello,
Please keep in mind that AmiBroker keeps in RAM
data already loaded (if possible).
So if you DECREASE the cache size in the settings
and re-run optimization
it won't affect your results until you actually
restart AmiBroker.
On the other hand INCREASING cache size should
give immediate effect
as AmiBroker will not need to flush cache.
Another factor is that Windows itself has
file-system cache that causes
that second reading of the same file may be
several times faster than first access.
This is so because Windows by itself keeps files
in RAM.
Windows cache mechanism depends on settings in "My
computer" as well
as on amount of memory, system used and if the
computer is desktop or laptop
(different default settings).
As to your question about besto config.
Let's calculate how many data you need to cache
database in RAM:
Each data bar: 32 bytes
# of symbols: 9000
# of years: 10
# of bar per year (EOD): 260
= 260 * 10 * 9000 * 32 = 748800000 bytes = 714 MB
So you would need 714 MB of free RAM to have
entire 10 year 9000 stock database
loaded into RAM.
Plus some additional memory for the system,
formula and resutls and you end up
with 1GB.
If you don't have that much memory and you are
interested in optimizations mainly
then it is actually better to shrink AmiBroker
cache to minimum size.
That way you will reduce swapping.
This is important because when you set high size
for cache it may happen that
Windows will need to start swapping and then
performance drops significantly.
All above assumes local database or fast data
plugins (Metastock, FastTrack, QP2)
If using slower plugins things may look different
because time required to communicate
with the 3rd party data source may dominate.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "tycanadian2003"
<tyler.schlosser@xxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, June 23, 2005 11:21 AM
Subject: [amibroker] AmiBroker Performance
Continued -- What Settings are Fastest?
> Hi again,
>
> Thanks for all the responses with respect to
my question about what
> affects the performance of AmiBroker with regards
to computing
> power. After doing several tests on a
few different computers, I am
> equally confused about which database
settings will offer the best
> performance in various situations. Here
are some specifics:
>
> On an Athlon XP ~2000+ laptop with 512MB RAM,
increasing the maximum
> RAM allowed under
Tools->Preferences->Data seemed to make a
> noticeable performance difference.
>
> On a P4 1.8 GHZ with 1 GB RAM and 10,000RPM
SCSI hard drive, any
> combination of changing max. RAM, bars loaded
(this was changed in
> the File->Database Settings options since
it overrides the one found
> in Preferences), and number of symbols to
load, seemed to make very
> little to no tangible performance difference.
On a roughly 8-minute
> backtest (run for two iterations in
Optimization mode to see if the
> second run is any faster than the first due
to possibly "loading it
> into memory"), any combination of these
options was all within 15
> seconds of all other combinations of
options. The same results were
> true on the Xeon 3.06 GHZ system with 2 GB
RAM.
>
> The amount of RAM used by AmiBroker under
Task Manager changed a LOT,
> but the time it took to finish a two-step
optimization changed only
> VERY slightly, if at all (this could be
attributed to the differences
> in myself opening and closing the task
manager window, etc.).
>
>
> My question is: What are the best
settings to use for a locally
> stored (C:) database with about 9,000 symbols
for 10 years of EOD
> data? Since I assume the PC specs
matter, what are the best settings
> to use for a PC with essentially unlimited
RAM vs. one with only
> 512MB vs. 1 GB of RAM?
>
> If anyone could offer some guidance
(Tomasz?), or possibly explain
> these results, I would appreciate it greatly.
>
> P.S. I agree that Athlons are probably
best as well, my PC at home
> is an Athlon and seemed to perform very well,
but sadly I am across
> the world right now (Switzerland) and just stealing a
bunch of
> computers here at work (which are all IBM
Intel-based) to run my
> AmiBroker stuff. So that's all I have
to benchmark, unfortunately.
>
>
>
>
> 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 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 other support material please check also:
http://www.amibroker.com/support.html
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 other support material please check also:
http://www.amibroker.com/support.html