Re: [amibroker] No performance increase with RAM Disk and CDI data???

["Tomasz Janeczko" <groups@xxxxxxxxxxxxx>]

Hello,

 

Windows has built-in caching on file system that caches in RAM content of every touched file.

Hence once file is accessed subsequent accesses are much faster. It can be seen in every app run / every file accessed for second time.

Best regards,
Tomasz Janeczko
amibroker.com

----- Original Message -----

From: Keith McCombs

To: amibroker@xxxxxxxxxxxxxxx

Sent: Sunday, November 15, 2009 9:33 AM

Subject: Re: [amibroker] No performance increase with RAM Disk and CDI data???

I don't know about Vista, but XP-64 can be a real pig when it comes to displaying very long results doing an 'Exploration'.  It is quite possible that you will get much faster times if you don't try to output as much information, even with essentially the same code. 

Experiment!! Can you run the same code, but at the very end, reduce the number of Buys by maybe two orders of magnitude?  And see how long it takes.

BTW, 150MB isn't very much data.  I just copied over 200MB from one HD to another.  The first time it took less than 7 seconds before windows explorer showed that all had been copied.  Second time and thereafter, less than 1 second.  Go figure?

If your RAM drive held a lot more data than your normal RAM, and the data you were using was much more than the available RAM, but would all fit in the RAM drive, then you might see some significant difference.

Then, to properly test the effect of your ram disk, you should probably reboot your computer between runs. Otherwise, AB may just be reading cached data from RAM, in either case.
I would suggest that you do the following and record time for each run, and each time to load RAM drive.
1. Reboot.
2. Run test using data from HD.
3. Load data onto RAM disk.
4. Run test using RAM disk data.
5. Reboot.
6. Load data onto RAM disk.
7. Run test using RAM disk data.
8. Run test using data from HD.

-- Keith

bestbobleonard wrote:

 

No performance increase with RAM Disk and CDI data.

If anyone is using these and gets better performance, please let me know. I'm running Vista. And created 500mb RAM disk. I copy the database to the Ram disk and reset Amibroker(5.2) to use it, but get no increase in performance. My one year database is about 150mb. An `Exploration' takes about 30 minutes either way. I'm beginning to think that my code size (2k+) might be the problem.
Thanks for any suggestions. Bob

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