Stability and Memory Pressure in 8.2

[riccardo]

On Wed, 2008-09-10 at 09:15 +0200, Marco Pesenti Gritti wrote:
> On Wed, Sep 10, 2008 at 4:29 AM, Gary C Martin <gary at garycmartin.com> wrote:
> >
> > OK, news is not great on the Activity front...
> >
> > SUMMARY: 759 vs 711 each Activity instance in 759 consumes an average
> > of 1Mb more memory than the same Activity running in 711, with
> > Write-57 reportedly taking significantly more than that (perhaps ~7Mb).
> >
> > Is top and/or ps memory usage calculated in the same way between these
> > builds? Could make collecting real data pretty painful.
> 
> Unfortunately not, there has been changes in the kernel. My
> understanding is that private memory will be the same, while
> calculation of shared memory has changed. Riccardo has a new kernel
> somewhere with instructions on how to install it on 711. That should
> make the memory usage comparable.
> 
> Marco

I used this newer kernel (as it accounts also for pss) for measurements
with ps_mem on build 703:
http://dev.laptop.org/~rlucchese/utils/703/kernel-2.6.25-20080501.3.olpc.231c7b715f4a8d0.i586.rpm

It can be installed on the xo with:
$ rpm -ivh kernel-....rpm
$ cp -a /boot/* /versions/boot/current/boot/

You will also have to update the ram disk image; you can follow the instructions at the bottom of
http://wiki.laptop.org/go/Kernel_Building


You may also want to try this patched ps_mem (shows pids and doesn't group entries by process name):
http://dev.laptop.org/~rlucchese/utils/ps_mem.py


riccardo