config: Change default memory size to 256 MB

Information
Submitter:	Andreas Hansson
Repository:	gem5
Branch:	default
Bugs:
Depends On:
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Groups:	Default
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Description

Changeset 9805:05b87da4607e
---------------------------
config: Change default memory size to 256 MB

This patch changes the default memory size to 256 MB to ensure that
the out-of-the-box fs.py configuration works for ARM systems (using
Realview PBX).

Testing Done

What goes wrong when 512 MB of memory is specified?

Ali Saidi July 5, 2013, 12:36 p.m. (July 5, 2013, 12:36 p.m.)

The memory map of that particular system only had 256MB of contiguous memory at address 0. More memory can't be contiguous and has to be at 2GB.

Amin Farmahini July 8, 2013, 11:10 a.m. (July 8, 2013, 11:10 a.m.)

Why not specifying memory size in the command line for that particular system? If we change the default memory size, it will cause trouble for those who rely on 512 MB default size.

Andreas Hansson July 9, 2013, 12:48 a.m. (July 9, 2013, 12:48 a.m.)

I would like to ensure that it continues to just work(tm) without having to add any parameters. The other option is to revert Nilay's change and remove the default option value. I'm fine with either, but I do not want users to have to add parameters just to get past the first hurdle.

Andreas Hansson July 15, 2013, 1:49 a.m. (July 15, 2013, 1:49 a.m.)

Is everyone happy with this going out as it is currently? I'd like to get things working again :-)

Andreas Hansson July 16, 2013, 3:58 p.m. (July 16, 2013, 3:58 p.m.)

Amin, since you raised concerns: are you ok with this going out or do you think it breaks something else?

Amin Farmahini July 16, 2013, 4:23 p.m. (July 16, 2013, 4:23 p.m.)

Well, it breaks some of my simulations because they are based on the assumption that default memory size is 512 MB. All I am saying is that some people (me :) ) might have assumed a default 512-MB memory, and now they need to change their simulation scripts because the default value changes. Maybe using a default memory size was a bad idea to begin with.
Overall, I am totally OK with this going out. I just wanted to mention it.

Andreas Hansson July 17, 2013, 12:31 a.m. (July 17, 2013, 12:31 a.m.)

Thanks Amin, I appreciate the feedback.

I'm stuck between a rock and a hard place it seems...

I'm inclined to suggest pushing this, thus prioritising the "out-of-box" experience, but I see how it could cause issues in other places. Any final words from anyone else?

You have a pending review.

Review Board 2.0.15

This change has been discarded.

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Status: Discarded