diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2023-05-31 13:58:44 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2023-07-19 09:43:58 +0200 |
| commit | 147f3efaa24182a21706bca15eab2f3f4630b5fe (patch) | |
| tree | 555ff76e8d3aabc2e62f43856e50ebff7e3bfbd9 /kernel/sched/debug.c | |
| parent | 99d4d26551b56f4e523dd04e4970b94aa796a64e (diff) | |
sched/fair: Implement an EEVDF-like scheduling policy
Where CFS is currently a WFQ based scheduler with only a single knob,
the weight. The addition of a second, latency oriented parameter,
makes something like WF2Q or EEVDF based a much better fit.
Specifically, EEVDF does EDF like scheduling in the left half of the
tree -- those entities that are owed service. Except because this is a
virtual time scheduler, the deadlines are in virtual time as well,
which is what allows over-subscription.
EEVDF has two parameters:
- weight, or time-slope: which is mapped to nice just as before
- request size, or slice length: which is used to compute
the virtual deadline as: vd_i = ve_i + r_i/w_i
Basically, by setting a smaller slice, the deadline will be earlier
and the task will be more eligible and ran earlier.
Tick driven preemption is driven by request/slice completion; while
wakeup preemption is driven by the deadline.
Because the tree is now effectively an interval tree, and the
selection is no longer 'leftmost', over-scheduling is less of a
problem.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230531124603.931005524@infradead.org
Diffstat (limited to 'kernel/sched/debug.c')
| -rw-r--r-- | kernel/sched/debug.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index e48d2b2db7bc..18efc6d0cc5a 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -582,9 +582,13 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p) else SEQ_printf(m, " %c", task_state_to_char(p)); - SEQ_printf(m, " %15s %5d %9Ld.%06ld %9Ld %5d ", + SEQ_printf(m, "%15s %5d %9Ld.%06ld %c %9Ld.%06ld %9Ld.%06ld %9Ld.%06ld %9Ld %5d ", p->comm, task_pid_nr(p), SPLIT_NS(p->se.vruntime), + entity_eligible(cfs_rq_of(&p->se), &p->se) ? 'E' : 'N', + SPLIT_NS(p->se.deadline), + SPLIT_NS(p->se.slice), + SPLIT_NS(p->se.sum_exec_runtime), (long long)(p->nvcsw + p->nivcsw), p->prio); |