On Thu, Apr 12, 2007 at 11:21:11PM +0530, Srivatsa Vaddagiri wrote: > Here's a respin of my earlier CPU controller to work on top of Paul > Menage's process container patches. > > Problem: > > Current CPU scheduler is very task centric, which makes it > difficult to manage cpu resource consumption of a group of > (related) tasks. > > For ex: with the current O(1) scheduler, it is possible for a user to > monopolize CPU simply by spawning more and more threads, causing DoS > to other users. > > > Requirements: > > A few of them are: > > - Provide means to group tasks from user-land and > specify limits of CPU bandwidth consumption of each group. > CPU bandwidth limit is enforced over some suitable time > period. For ex: a 40% limit could mean the task group's usage > is limited to 4 sec every 10 sec or 24 sec every minute. > > - Time period over which bandwidth is controlled to each group > to be configurable (?) > > - Work conserving - Do not let the CPU be idle if there are > runnable tasks (even if that means running task-groups that > are above their allowed limit) > > - SMP behavior - Limit to be enforced on all CPUs put together > > - Real-time tasks - Should be left alone as they are today? > i.e real time tasks across groups should be scheduled as if > they are in same group > > - Should cater to requirements of variety of workload characteristics, > including bursty ones (?) > > > Salient points about this patch: > > - Each task-group gets its own runqueue on every cpu.
how does that scale for, let's say 200-300 guests on a 'typical' dual CPU machine? > - In addition, there is an active and expired array of > task-groups themselves. Task-groups that have expired their > quota are put into expired array. how much overhead does that add to the scheduler, cpu and memory wise? > - Task-groups have priorities. Priority of a task-group is the > same as the priority of the highest-priority runnable task it > has. This I feel will retain interactiveness of the system > as it is today. > > - Scheduling the next task involves picking highest priority > task-group > from active array first and then picking highest-priority task > within it. Both steps are O(1). how does that affect interactivity? > - Token are assigned to task-groups based on their assigned > quota. Once they run out of tokens, the task-group is put > in an expired array. Array switch happens when active array > is empty. > > - SMP load-balancing is accomplished on the lines of smpnice. what about strict CPU limits (i.e. 20% regardless of the idle state of the machine) TIA, Herbert > Results of the patch > ==================== > > Machine : 2way x86_64 Intel Xeon (3.6 GHz) box > > Note: All test were forced to run on only one CPU using cpusets > > 1. Volanomark [1] > > ------------------------------------------------------------------------------ > Group A [50% limit] Group B [50% limit] > > Elapsed time 35.83 sec 36.6002 > Avg throughput 11179.3 msg/sec 10944.3 msg/sec > > ------------------------------------------------------------------------------ > > > ------------------------------------------------------------------------------ > Group A [80% limit] Group B [20% limit] > > Elapsed time 23.4466 sec 36.1857 > Avg throughput 17072 msg/sec 11080 msg/sec > > ------------------------------------------------------------------------------ > > 2. Kernel compilation > > > ------------------------------------------------------------------------------ > Group A [50% limit] Group B [50% limit] > time -p make -j4 bzImage time -p make -j8 bzImage > > real 771.00 sec 769.08 sec > > ------------------------------------------------------------------------------ > > > ------------------------------------------------------------------------------ > Group A [80% limit] Group B [20% limit] > time -p make -j4 bzImage time -p make -j8 bzImage > > real 484.12 sec 769.70 sec > > ------------------------------------------------------------------------------ > > > > -- > Regards, > vatsa ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ ckrm-tech mailing list https://lists.sourceforge.net/lists/listinfo/ckrm-tech
