Add weights to layers and use the infeasible weights crate to properly
apply weights during contention to prevent starvation.
Signed-off-by: Daniel Hodges <hodges.daniel.scott@gmail.com>
`layer_core_order` provided multiple core growth implementation
Break it up into smaller function. Also, attach the method to
LayerGrowthAlgo. And `LayerCoreOrderGenerator` is added to make future
growth algo extension easy.
Signed-off-by: Ming Yang <minos.future@gmail.com>
Remove a short-circuit in cpu_to_dom_id that will return domain id 0 for
any input.
This fixes a crash of scx_rusty when running with a single domain and
any CPU is offline.
Signed-off-by: Fredrik Lönnegren <fredrik@frelon.se>
"struct task_struct *p" isn't used within the function
"task_load_adj()". Delete the function parameter for cleaner code.
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
Use scx_utils::NR_CPU_IDS to iterate whole CPUs and separately count the
number of online CPUs to support CPU hotplug correctly.
Signed-off-by: Changwoo Min <changwoo@igalia.com>
`#stat_doc` extends the document from stat desc property.
Add this attribute macro to the remaining Stats structs.
Signed-off-by: Ming Yang <minos.future@gmail.com>
task_avg_nvcsw() was incorrectly returning a bool instead of u64,
limiting the impact of the lowlatency boost.
Fix it by returning the proper type (u64).
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
When a task is the last one running on a CPU and still wants to
continue, allow it to run and replenish its time only if the used CPU is
part a fully idle SMT core.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
During ttwu, the kernel may decide to skip ->select_task_rq() (e.g.,
when only one CPU is allowed or migration is disabled). This causes to
call ops.enqueue() directly without having a chance to call
ops.select_cpu().
Therefore, introduce a new flag (select_cpu_done) in the local task
context to determine if ops.select_cpu() was bypassed and, in that case,
attempt to find an idle CPU directly from ops.enqueue().
In the future this information will be supplied by the kernel through a
special enqueue flag (SCX_ENQ_CPU_SELECTED) [1]. However, the custom
flag in the local task context ensures to reliably determine the same
information, even on older kernels where this flag is not available.
[1] https://lore.kernel.org/lkml/20240928003840.GA2717@maniforge/T
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
Fix a bug in cache initialization where the first node would repeated
get all CPUs added to the mask. Refactor some consts to be more clear.
Signed-off-by: Daniel Hodges <hodges.daniel.scott@gmail.com>
It seems that with the latest kernel the per-CPU DSQ stall while
executing sched_setaffinity() doesn't happen anymore.
Therefore, get rid of the temporary workaround introduced by commit
86db45f ("scx_rustland_core: prevent deadlock with per-CPU DSQs and CPU
affinity") and restore the old behavior, which offers more fair
scheduling policy.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
When finding a victim candidate for preemption, a randomly chosen
candidate could be out of valid CPU range due to CPU offline, etc. In
this case, try another CPU randomly.
Signed-off-by: Changwoo Min <changwoo@igalia.com>
The doc of scx_layered `Opt` is out of sync.
Implement attribute macro #stat_doc to generate doc from the `desc`
property.
Apply #stat_doc to `LayerStats` and `SysStats in scx_layered.
Signed-off-by : Ming Yang <minos.future@gmail.com>
