Maximum Ram disc size

The maximum size for a Ram disc is currently set at 128MiB. It would be useful if this could be raised to say 256MiB.

This would enable the OMAP rom to be built from a ram disc. This should give a noticable reduction in build time.

Have you tried Memphis 3?

For some reason memphis is much slower. Doesn’t seem to like writing or deleting lots of small files.

There’s already a wishlist thread about this here :)

It looks easy enough to increase the maximum size of the ramdisc if you want to do some testing (see Kernel.s.NewReset, around line 1645). But as Adrian says in the linked thread I’m not sure if you’d see much of an improvement unless you were to make the area cacheable as well (i.e. force it to use the AP_RAMDisc_SA flags).

If those changes give a significant reduction in build times then maybe we should bump “rework RAMFS & memory-to-memory DMA” a bit further up the todo list :)

I must remember to check for previous threads!

A rom build now takes about 11 minutes instead of 45. The only problem is the rom produced wouldn’t boot. :-(

Using the ram disc also enabled me to bump up the CPU clock to 720Mhz. Normally USB turns off a few seconds into the build at more than 500Mhz.

What clock speed were you using when you built the bad ROM? If you were overclocking then it’s probably a good idea to try again at 600MHz just in case your OMAP isn’t as tolerant to overclocking as most other peoples seems to be (although I’d imagine a fully RAM-based ROM build would be much more of a CPU stress test than the other things that people have tried so far)

Also a 300% reduction in build time is quite a lot, so it’s probably a good idea to check the build log for any errors, e.g. 75% of files failing to build ;)

The only other thing I can think of is that it might be the dependencies bug – so check if you’ve got AMU 5.28 or above.

Turns out it was working all along. My SD card needed reformatting. :-)

A worthwhile speed up. For comparison a build take 15 minutes at 500Mhz plus about 5 minutes to sync the folder, with the added bonus I can carry on using RISC OS while it builds.