On Wed, 8 May 2019 10:04:36 +0200 Juri Lelli <[email protected]> wrote:
> Hi Luca, > > On 06/05/19 06:48, Luca Abeni wrote: > > From: luca abeni <[email protected]> > > > > Currently, the SCHED_DEADLINE scheduler uses a global EDF scheduling > > algorithm, migrating tasks to CPU cores without considering the core > > capacity and the task utilization. This works well on homogeneous > > systems (SCHED_DEADLINE tasks are guaranteed to have a bounded > > tardiness), but presents some issues on heterogeneous systems. For > > example, a SCHED_DEADLINE task might be migrated on a core that has > > not enough processing capacity to correctly serve the task (think > > about a task with runtime 70ms and period 100ms migrated to a core > > with processing capacity 0.5) > > > > This commit is a first step to address the issue: When a task wakes > > up or migrates away from a CPU core, the scheduler tries to find an > > idle core having enough processing capacity to serve the task. > > > > Signed-off-by: luca abeni <[email protected]> > > --- > > kernel/sched/cpudeadline.c | 31 +++++++++++++++++++++++++++++-- > > kernel/sched/deadline.c | 8 ++++++-- > > kernel/sched/sched.h | 7 ++++++- > > 3 files changed, 41 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c > > index 50316455ea66..d21f7905b9c1 100644 > > --- a/kernel/sched/cpudeadline.c > > +++ b/kernel/sched/cpudeadline.c > > @@ -110,6 +110,22 @@ static inline int cpudl_maximum(struct cpudl > > *cp) return cp->elements[0].cpu; > > } > > > > +static inline int dl_task_fit(const struct sched_dl_entity *dl_se, > > + int cpu, u64 *c) > > +{ > > + u64 cap = (arch_scale_cpu_capacity(NULL, cpu) * > > arch_scale_freq_capacity(cpu)) >> SCHED_CAPACITY_SHIFT; > > + s64 rel_deadline = dl_se->dl_deadline; > > + u64 rem_runtime = dl_se->dl_runtime; > > This is not the dynamic remaining one, is it? Right; I preferred to split this in two patches so that if we decide to use only the static task parameters (dl_deadline and dl_runtime) I can simply drop a patch ;-) Luca > > I see however 4/6.. lemme better look at that. > > Best, > > - Juri
