Hi,

We’re debugging an in-house application that makes use of hard limit extensively. We ran into a lot of timing windows (all our own making) and we use runq -g command a lot. The current runq -g display only the RBROOT pointer. It really is a bit inconvenient to traverse the task_group hierarchy. It would be nice to have the command also display the corresponding task_group, cfs_rq pointer (at a minimum). Since the way we crash the system by messing up the nr_running and h_nr_running, so we also display those two fields at the same time. Here’s an example of before and after.

CPU 4

  CURRENT: PID: 0      TASK: ffff8840668c0380  COMMAND: "swapper"

  TASK_GROUP RT_RQ: ffff8800027d3820

  RT PRIO_ARRAY: ffff8800027d3820

     [no tasks queued]

  TASK_GROUP CFS_RQ: ffff8800027d36e0

  CFS RB_ROOT: ffff8800027d3710

     GROUP CFS RB_ROOT: ffff883ff69bcc30 <TDAT>

        GROUP CFS RB_ROOT: ffff884006290e30 <User>

           GROUP CFS RB_ROOT: ffff88400641c430 <TDWMVP1>

              GROUP CFS RB_ROOT: ffff88400646b030 <ServDown1:0>

                 GROUP CFS RB_ROOT: ffff884006492630 <ServOrder1:1>

                    GROUP CFS RB_ROOT: ffff883ff058fe30 <TDWMWD57> (THROTTLED)

                       GROUP CFS RB_ROOT: ffff88047889ee30 <S:WD:3d:35fa>

                          [120] PID: 27655  TASK: ffff8805078ce2c0  COMMAND: "actmain"

                                <<< more throttled groups removed >>>

CPU 4

  CURRENT: PID: 0     CFS: ffff8800027d36e0 TASK: ffff8840668c0380  COMMAND: "swapper"

  TASK_GROUP RT_RQ: ffff8800027d3820

  RT PRIO_ARRAY: ffff8800027d3820

     [no tasks queued]

  TASK_GROUP CFS_RQ: ffff8800027d36e0

  CFS RB_ROOT: ffff8800027d3710

     GROUP: ffff88405394d000 CFS: ffff883ff69bcc00 RB_ROOT: ffff883ff69bcc30 <TDAT> (0 0)

        GROUP: ffff88405906c400 CFS: ffff884006290e00 RB_ROOT: ffff884006290e30 <User> (0 0)

           GROUP: ffff884055081000 CFS: ffff88400641c400 RB_ROOT: ffff88400641c430 <TDWMVP1> (0 0)

              GROUP: ffff884055081c00 CFS: ffff88400646b000 RB_ROOT: ffff88400646b030 <ServDown1:0> (0 0)

                 GROUP: ffff8840580fd400 CFS: ffff884006492600 RB_ROOT: ffff884006492630 <ServOrder1:1> (0 0)

                    GROUP: ffff884058f58c00 CFS: ffff883ff058fe00 RB_ROOT: ffff883ff058fe30 <TDWMWD57> (7 9)  (THROTTLED)

                       GROUP: ffff8808fb976000 CFS: ffff88047889ee00 RB_ROOT: ffff88047889ee30 <S:WD:3d:35fa> (1 1)

                          [120] PID: 27655  TASK: ffff8805078ce2c0  COMMAND: "actmain"

                                <<< more throttled groups removed >>>

I have attached the patch we use to display additional information. Could you please take a look at my proposal to see if it is possible that you include this kind of display format.

Thanks,

Anthony