On Wed, Apr 06, 2011 at 11:50:21AM -0700, Vaibhav Nagarnaik wrote: > All > The cgroup functionality is being used widely in different scenarios. It also > is being integrated with other parts of kernel to take advantage of its > features. One of the areas that is not yet aware of cgroup functionality is > the ftrace framework. > > Although ftrace provides a way to filter based on PIDs of tasks to be traced, > it is restricted to specific tracers, like function tracer. Also it becomes > difficult to keep track of all PIDs in a dynamic environment with processes > being created and destroyed in a short amount of time. > > An application that creates many processes/tasks is convenient to track and > control with cgroups, but it is difficult to track these processes for the > purposes of tracing. And if child processes are moved to another cgroup, it > makes sense to trace only the original cgroup. > > This proposal is to create a file in the tracing directory called > set_trace_cgroup to which a user can write the path of an active cgroup, one > at a time. If no cgroups are specified, no filtering is done and all tasks are > traced. When a cgroup path is added in, it sets a boolean tracing_enabled for > the enabled cgroup in all the hierarchies, which enables tracing for all the > assigned tasks under the specified cgroup. > > Though creating a new file in the directory is not desirable, but this > interface seems the most appropriate change required to implement the new > feature. > > This tracing_enabled flag is also exported in the cgroupfs directory structure > which can be turned on/off for a specific hierarchy/cgroup combination. This > gives control to enable/disable tracing over a cgroup in a specific hierarchy > only. > > This gives more fine-grained control over the tasks being traced. I would like > to know your thoughts on this interface and the approach to make tracing > cgroup aware. So I have to ask, why can't you use perf events to do tracing limited on cgroups? It has this cgroup context awareness. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
