On Tue, Aug 26, 2014 at 12:06:52PM +0100, Vincent Guittot wrote:
Add new statistics which reflect the average time a task is running on the CPU and the sum of the tasks' running on a runqueue. The latter is named usage_avg_contrib.
This patch is based on the usage metric that was proposed in the 1st versions of the per-entity load tracking patchset but that has be removed afterward. This version differs from the original one in the sense that it's not linked to task_group.
The rq's usage_avg_contrib will be used to check if a rq is overloaded or not instead of trying to compute how many task a group of CPUs can handle
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org
I should have read this patch before I did almost the same patch for as part a series to introduce scale-invariance which I am about to post :(
The only difference I see is slightly different naming and that, AFAICT, task group usage is not accounted for in this patch. Can we add the support for task groups as well? I can provide a patch based on this one if you want.
Also, since more than half this patch comes directly from PJT's original patch I would add "by Paul Turner pjt@google.com" somewhere in the text above.
[...]
+static inline void __update_task_entity_usage(struct sched_entity *se) +{
- u32 contrib;
- /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */
- contrib = se->avg.running_avg_sum * scale_load_down(SCHED_LOAD_SCALE);
- contrib /= (se->avg.runnable_avg_period + 1);
- se->avg.usage_avg_contrib = scale_load(contrib);
+}
+static long __update_entity_usage_avg_contrib(struct sched_entity *se) +{
- long old_contrib = se->avg.usage_avg_contrib;
- if (entity_is_task(se))
__update_task_entity_usage(se);
Groups are never updated?
As said above. I have code that does it.
Morten
- return se->avg.usage_avg_contrib - old_contrib;
+}