"Lots of scheduler updates in the past few days, done by many people," noted Ingo Molnar, going on to describe the more significant updates. "Most importantly, the SMP latency problems reported and debugged by Mike Galbraith should be fixed for good now." Ingo noted that the current code base was looking stable and was likely to be merged into the upcoming 2.6.24 kernel, "so please give it a good workout and let us know if there's anything bad going on. (If this works out fine then i'll propagate these changes back into the CFS backport, for wider testing.)" He went on to describe the other main changes in the development branch of the process scheduler:
"I've also included the latest and greatest group-fairness scheduling patch from Srivatsa Vaddagiri, which can now be used without containers as well (in a simplified, each-uid-gets-its-fair-share mode). This feature (CONFIG_FAIR_USER_SCHED) is now default-enabled.
"Peter Zijlstra has been busy enhancing the math of the scheduler: we've got the new 'vslice' forked-task code that should enable snappier shell commands during load while still keeping kbuild workloads in check."
"The cfs core has been enhanced since quite sometime now to understand task-groups and [to] provide fairness to such task-groups," began Srivatsa Vaddagiri, "what was needed was an interface for the administrator to define task-groups and specify group 'importance' in terms of its cpu share. The patch below adds such an interface."
Srivatsa requested that his patch be merged into Andrew Morton's -mm tree to receive more testing, "note that the load balancer needs more work, esp to deal with cases like 2-groups on 4-cpus, one group has 3 tasks and other having 4 tasks. We are working on some ideas, but nothing to share in the form of a patch yet. I felt sending this patch out would help folks start testing the feature and also improve it."