Power Saving modes on BBB?
gaborpaller at gmail.com
Thu Jul 30 12:39:18 UTC 2015
Linux localhost.localdomain 3.19.0-23-generic #24-Ubuntu SMP Tue Jul 7
18:56:34 UTC 2015 armv7l armv7l armv7l GNU/Linux"
Is that the latest 15.04 that came out just some days ago or is this a
kernel that you compiled?
"well, i'm just trying to find out if "TI SDK" means you have your own
rootfs or if you just put vmlinuz and the modules from the TI SDK into
an already installed snappy system ...
I tried to install the kernel/modules that come with TI SDK into a snappy
system but I failed. The kernel failed to start and I was not able to
figure out the reason.
So at the end I just followed the instructions.
This yielded an entire bootable system. That's how I made my measurements.
On Thu, Jul 30, 2015 at 2:23 PM, Oliver Grawert <ogra at ubuntu.com> wrote:
> Am Donnerstag, den 30.07.2015, 12:52 +0200 schrieb Gábor Paller:
> > Linux localhost.localdomain 3.19.0-18-generic #18-Ubuntu SMP Tue May
> ah, that might be the issue ;)
> (BeagleBoneBlack)ubuntu at localhost:~$ uname -a
> Linux localhost.localdomain 3.19.0-23-generic #24-Ubuntu SMP Tue Jul 7
> 18:56:34 UTC 2015 armv7l armv7l armv7l GNU/Linux
> > This is a 15.04 Snappy on BBB without any kernel hacking.
> > "is this under the same userspace too (i.e. are you sure it is kernel
> > induced and not some bad userspace component) ?"
> > My test is the following. I created an SD card from the stock Snappy
> > image, flashed it and booted it. I waited for the boot sequence to
> > finish and waited for the idle prompt. I measure 340 mA of
> > consumption. I did the same with the TI SDK and I measure 250 mA.
> > Hence the 40% difference.
> > As with any Linux distribution it is not only the "kernel" that is
> > running in any of these cases but a bunch of drivers/daemons too. But
> > there is no userspace component in these cases, at least I did not
> > install/run any.
> well, i'm just trying to find out if "TI SDK" means you have your own
> rootfs or if you just put vmlinuz and the modules from the TI SDK into
> an already installed snappy system ...
> there can be plenty differences on kernel level (does the TI kernel
> actually have all needed apparmor patches for example). but i would
> expect userspace difference too if you dont use the very same rootfs for
> measuring both.
> to identify if the higher power consumption is a kernel or userspace
> thing you can indeed only measure reliably by using the same environment
> to run the different kernels in, else you might for example have
> userspace bits that turn different knobs in sysfs on boot etc which will
> definitely get you different hardware behavior.
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