Programs on one or many cores?

Any technical questions about the Epiphany chip and Parallella HW Platform.

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Programs on one or many cores?

Postby baseballguy » Mon Jul 14, 2014 8:01 pm

Hi,

I was running some of the programs from this website (https://github.com/parallella/parallella-examples) like aobench, mandelbrot, and more. I was wondering if these programs are being excecuted on a single core or if they are utilizing all 16 cores. Is there a way to check the performance of each core?

Thanks
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Re: Programs on one or many cores?

Postby gceline » Mon Jul 14, 2014 9:35 pm

Most are running on 16 cores - take a look at the code to see how this is implemented
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Re: Programs on one or many cores?

Postby baseballguy » Mon Jul 14, 2014 11:04 pm

Sorry, I'm kind of new to this parallel programming. What kind of things should I look for in the code to indicate that they are using more than one core?
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Re: Programs on one or many cores?

Postby baseballguy » Mon Jul 14, 2014 11:26 pm

Also, is there any way to limit the number of cores used? For example, I want to compare a program running with only 4 cores as opposed to 16. Is that possible?
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Re: Programs on one or many cores?

Postby greytery » Tue Jul 15, 2014 12:32 am

Yep. Just check the SDK manual. There's a section in e-loader on 'workgroups', which allows you to load the programs on to a specific set of cores.
Not that I've tried it yet :(
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Re: Programs on one or many cores?

Postby shodruk » Tue Jul 15, 2014 2:26 am

baseballguy wrote:Also, is there any way to limit the number of cores used? For example, I want to compare a program running with only 4 cores as opposed to 16. Is that possible?


For example: mandelbrot
https://github.com/parallella/parallell ... rot/host.c

Modify these lines

#define ROWS 4
#define COLS 4

4 x 4 = 16 cores.

#define ROWS 1
#define COLS 1

1 x 1 = 1 core.
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Re: Programs on one or many cores?

Postby baseballguy » Tue Jul 15, 2014 1:28 pm

Thanks for the reply. I appreciate it. I tried to change the number of cores like you said. I saved it,

https://fbcdn-sphotos-h-a.akamaihd.net/ ... 14d9c68337

and tried running it again but I didnt see a change in the performance or anything. Is there a way to see the "statistics" as in the resolution, frames, iterations, etc like in your video.

https://www.youtube.com/watch?v=hFWIC3RF0f8
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Re: Programs on one or many cores?

Postby baseballguy » Tue Jul 15, 2014 1:38 pm

I just realized that there are now two host.c files

https://fbcdn-sphotos-h-a.akamaihd.net/ ... 6ae732df3c
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Re: Programs on one or many cores?

Postby 9600 » Tue Jul 15, 2014 2:03 pm

baseballguy wrote:I just realized that there are now two host.c files


Not exactly: the one which terminates with a tilde is not the same as the one without and will be a backup created by the editor.

Regards,

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Re: Programs on one or many cores?

Postby baseballguy » Tue Jul 15, 2014 2:26 pm

Does anyone know what the problem is?

I have a feeling is has something to do with host.c and host.c~.

https://fbcdn-sphotos-h-a.akamaihd.net/ ... 95b473d789

Every time I edit one of the files to try to change the cores, another file with the same name with an added tilde is created (I did the same with aobench)

https://fbcdn-sphotos-h-a.akamaihd.net/ ... 0fc87521a2

I viewed the contents of both files and found the the file WITHOUT the tilde had the modified cores (1) but the one WITH the tilde had the same number of cores as in the beginning (16)
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