Beaglebone AI Memory 1GB Ram?

dpstorey over 4 years ago

I thought the Beaglebone AI is meant to have 1GB RAM?

when I run free -m, I get the following:

total used free shared buff/cache available

Mem: 577 244 54 38 278 282

Swap: 0 0 0

I only see 57% of the memory! Where is the other 43%?

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mp2100 over 4 years ago in reply to mp2100 +1

Found the forum discussion: https://beagleboard.org/discuss/#bone_forum_embed quote from Jason, November 2019: So, what's consuming the other 413M? Can I get some of that back? Thanks. By default, it is…

gdstew over 4 years ago

As far as I know it should be 1 GB. See if the command cat /proc/meminfo gives you a different result. It prints out a lot of information,
what you are looking for should be at the top of the list. If it doesn't then you probably have a hardware problem.
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mp2100 over 4 years ago

I will have to find the particular beaglebone discussion for details, but Jason K. gave some information about this. Installed RAM is 1 GB, but the PRU are allocated some of that, the EVE engines are allocated some. The rest is left for Linux to use.
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mp2100 over 4 years ago in reply to mp2100

Found the forum discussion:
https://beagleboard.org/discuss/#bone_forum_embed

quote from Jason, November 2019:

So, what's consuming the other 413M? Can I get some of that back? Thanks.

By default, it is reserved for the C66/EVE processors. There has been much discussion about making it more dynamically allocatable, but, for now, it would require editing the device tree.

In specific, these lines would need to be removed or marked "disabled" by an overlay: https://github.com/beagleboard/BeagleBoard-DeviceTrees/blob/2d1271702ce962160fe3a632ebee394207e2714b/src/arm/am5729-beagleboneai.dts#L38-L101

Due to a lack of foresight, the nodes don't have labels, which makes creating an overlay a bit more difficult.

In the default image, you can go to /opt/source/dtb-4.14-ti, edit src/arm/am5729-beagleboneai.dts to remove those lines, make, sudo make install and reboot and you should get all of the memory back.
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