On Wed, Apr 18, 2012 at 10:44 PM, Sha Zhengju <handai.szj@xxxxxxxxx> wrote: > 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. I have a different version of exposing per-cgroup /proc/stat (parts of them come from your patchset : ) ). I can sent them out if necessary. Thanks, Sha -- 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
