On Mon, Apr 9, 2012 at 6:25 PM, Glauber Costa <glommer@xxxxxxxxxxxxx> wrote: > This patch aims at exposing stat information per-cgroup, such as: > * idle time, > * iowait time, > * steal time, > * # context switches > and friends. The ultimate goal is to be able to present a per-container view of > /proc/stat inside a container. With this patch, everything that is needed to do > that is in place, except for number of tasks. > > For most of the data, I achieve that by hooking into the schedstats framework, > so although the overhead of that is prone to discussion, I am not adding anything, > but reusing what's already there instead. The exception being that the data is > now computed and stored in non-task se's as well, instead of entity_is_task() branches. > However, I expect this to be minimum comparing to the alternative of adding new > hierarchy walks. Those are kept intact. > > The format of the new file added is the same as the one recently > introduced for cpuacct: > > cpu0.idle X > cpu0.steal Y > ... > cpu1.idle X1 > cpu1.steal Y1 > ... > You define the idle time as the sum of task's sleeping time which i think it needs to discuss. It changes the current meaning of idle time which might be confusing and can not reflect the the actual cpu busy-idle situation. IMHO, idle time can just be the true system value. Personally I prefer to your last version in the way of computing idle time (http://thread.gmane.org/gmane.linux.kernel/1194838). And iowait can be computed in the similar way. As to steal time, "Steal time is the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor". Speaking from the point of view of resource controlling(isolation), cgroup is a lightweight method towards virtualiztion, so I think obeying its primitive meaning is more appropriate: the time not servicing me including time stolen by the tasks of other cgroup. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
