On 15 February 2012 00:33, Zygmunt Krynicki zygmunt.krynicki@linaro.org wrote:
Prompted by Paul I've decided to try a bigLITTLE config. My test did not end up very good:
- I've tried the RealView Express A15x1-A7x1 model
NB that I think the plan for big.LITTLE models is to use a prebuilt RTSM, which should look the same as a binary built from the example models, it's just a pre-cooked binary supplied by ARM rather than built by us.
- It has different options that can be passed to model shell, needles
to say they are not compatible. I tweaked my semihosting line to look like this:
-C coretile.cluster0.cpu0.semihosting-cmd_line="--kernel $KERNEL -- console=ttyAMA0 mem=512M ip=dhcp root=/dev/nfs nfsroot=$NFSROOT,tcp rw earlyprintk $@"
Yeah, the parameters are specific to the components within the model, so they vary depending on the structure of the model.
- I did not get the kernel to boot at all, I suspect that our boot
wrapper is not compatible or I mis-configured the kernel or something in between. I did not even get a X11 terminal window as I usually always get.
Yes, we've been clear for some time that the bootwrapper needs changes to work with big.LITTLE (in fact I'm not entirely sure whether the switcher code counts as part of the 'kernel' or not). Dave probably knows more about the status here (I suspect there's some working code somewhere, just maybe not in the git.linaro.org boot-wrapper or whichever kernel you tried).
-- PMM