On 23 August 2011 14:41, Daniel Lezcano <daniel.lezc...@linaro.org> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > Hi all, > > I did the following cpuset configuration: > > if [ ! -d /sys/fs/cgroup ]; then > echo "cgroup not supported by the kernel" > else > mount -t cgroup cgroup /sys/fs/cgroup > > # needed to have the cgroup values inherited from > # the parent cgroup > echo 1 > /sys/fs/cgroup/cgroup.clone_children > > # create an empty cgroup 'cpu0' > mkdir /sys/fs/cgroup/cpu0 > > # create an empty cgroup 'cpu1' > mkdir /sys/fs/cgroup/cpu1 > > # assign cpu number '0' for cgroup cpu0 > echo 0 > /sys/fs/cgroup/cpu0/cpuset.cpus > > # move outself to this new cgroup > echo $$ > /sys/fs/cgroup/cpu0 > > # move all the tasks to the cpu0 cgroup > # kernel threads won't be moved, don't worry about the > # the errors. > for i in $(cat /sys/fs/cgroup/tasks); do > echo $i > /sys/fs/cgroup/cpu0/tasks || echo "failed to > add pid $i/$(cat /proc/$i/comm)" > done > > # assign a cpu for cgroup cpu1 > echo 1 > /sys/fs/cgroup/cpu1/cpuset.cpus > > # make cpu1 exclusive so processes belonging > # to the other cgroups won't be able to use it. > echo 1 > /sys/fs/cgroup/cpu1/cpuset.cpu_exclusive > fi > > > At this point, most of the processes have been moved to the 'cpu0' > cgroup and will use the cpu0 only. That does not prevent the cpu1 to be > used by the kernel threads. Any application launched will run on cpu0 only. > > After running 10 infinite loops, the cpu accounting gives: > > cat /sys/fs/cgroup/cpu0/cpuacct.usage_percpu > 418943579549 0 > > cat /sys/fs/cgroup/cpu1/cpuacct.usage_percpu > 0 0 > > But the system is: > > cat /sys/fs/cgroup/cpuacct.usage_percpu > 456741213041 30734572583 >
You should get the values before and after your tests and compute the difference. You should also read value of /sys/fs/cgroup/ level where we still have kernel threads if i have understand your comments > My guess is that reflects the kernel booted with the two cpus before we > created the cgroup. I am investigation the 'isolcpus' kernel parameter. > > I think it is a good starting point to do some consumption measurements. > > Mike, Vincent, what do you think ? Do you need more informations or > anything else ? > Yes it's a good starting point. One key point will be to be sure to not use cpu1. In fact, we mainly have 2 power efficient states: use equally the 2 cpus or use only one cpu and put the other one in a low power state. Vincent > Thanks > -- Daniel > > - -- > <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | > <http://twitter.com/#!/linaroorg> Twitter | > <http://www.linaro.org/linaro-blog/> Blog > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.11 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ > > iQEcBAEBAgAGBQJOU6AVAAoJEAKBbMCpUGYAbQoH/0NeKLecIuMT57B/w1Jid/bn > yzqD3zwMt0EfUwfsU6H5dAYgumMzKmWWXR9+7FvYhkcckXfzumiMLFKhIybrUSz/ > LW7ymHwxXcHWqBTKwMCasHzo9WhlRTlLA1pGAqo0qtG1IBpalE68ZRwItdY/HSOw > 0mDGoegq4DHQtcF64XwGRZJo2wAsamtlWGejFdqLQU4FONyYI42rLXMNAG6VD3vG > CJrIudH5hLz3ZBdHYeRB6kWaj1O4skAW6fgySASiqFWoEaZzvT/7UuVBEYawpuyT > Pm+U9OHAfHUWfnyDASFfx6ZQKRS5Uk40XzThjGgwoo598EN8FXZD3N6UZ1WmL2U= > =H00Z > -----END PGP SIGNATURE----- > _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
