Since scx_rustland_core enables setting a time slice on a per-task basis
during task dispatch, there's no need to maintain a global time slice in
the BPF component. Instead, a global time slice can simply be managed in
user-space, achieving the same outcome.
Therefore, drop the global slice_us property from BpfScheduler to
simplify the API.
NOTE: if a time slice is not specified for a task, SCX_SLICE_DFL will be
used by default.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
The update_tasks() API is somewhat confusing, so replace it with a
clearer API, notify_complete().
This new API will return control to the BPF component and inform it
about the number of tasks still pending in the user-space scheduler.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
The low-power API is a bit of a hack implemented purely in the BPF
layer, this should be better re-implemented with some concepts of
topology awareness.
Therefore, get rid of this API for now.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
The current API used to notify the user-space scheduler when a task
exits is really confusing (setting a negative value in
queued_task_ctx.cpu), and it's also possible to detect task exiting
events from user-space (or check in procfs, even if it's slower).
In any case, a better API should be provided for this, so drop the
current one for now.
NOTE: this will cause additional memory usage for scx_rustland, but it
can be fixed/addressed later in a separate commit (i.e., providing a
periodic garbage collector for the unused task entries).
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
Instead of determining the task time slice in ops.enqueue(), refresh the
time slice immediately before the task is started on its assigned CPU in
ops.running().
This ensures to apply the exact time slice specified by the user-space
scheduler and the sched_ext core will never implicitly dispatch tasks
using SCX_SLICE_DFL.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
Allow user-space scheduler to pick an idle CPU via
self.bpf.select_cpu(pid, prev_task, flags), mimicking the BPF's
select_cpu() iterface.
Also remove the full_user option and always rely on the idle selection
logic from user-space.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
OM labels() was called with an array which is then incorrectly interpreted
as a single label. Unpack it to list of arguments. While at it, make error
reporting a bit more robust.
LazyLock is stable but has become so only very recently and can trigger
build errors on not-too-old stable rustc's which are still in wide use.
Let's use lazy_static instead for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
With Intel Turbo Boost enabled, some CPUs might show a higher maximum
frequency than others, even if they are not actually faster cores. This
can potentially confuse some auto-detection logic for distinguishing
between fast and slow cores in certain schedulers.
The base CPU frequency reported in
/sys/devices/system/cpu/cpuN/cpufreq/base_frequency represents a more
reliable indicator for identifying truly fast and slow cores.
To address this, provide a new base_freq() method in the struct Cpu,
which will return the base operational frequency of a CPU when Turbo
Boost is present. If Turbo Boost is not available, base_freq() will
return the maximum frequency, functioning the same as max_freq().
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
- Add static NR_CPU_IDS and NR_CPUS_POSSIBLE to topology.
- Fix comment for Topology::nr_cpu_ids(). Was missing a negation.
- cpumaks should be sized by nr_cpus_ids, not num_possible_cpus and the
number can't change while the system is running. Drop cpumask.nr_cpus and
use *NR_CPU_IDS everywhere.
- Update scx_utils/build.rs so that 12 char SHA1 is generated instead of
full one.
- Add --version to scx_rusty. Use custom one as we don't want to use the
default cargo version one.
Allow to format a Cpumask as an hex string, implementing the proper
formatter LowerHex / UpperHex traits.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
Add the L2 / L3 cache id to the Cpu struct, to quickly determine the
cache nodes associated to each CPU.
Signed-off-by: Andrea Righi <andrea.righi@linux.dev>
open_ops tracks which ops have been opened by the client session; however,
it was being created on each handle_request() making every request to open
each time. Fix it by moving it to the caller.
- Allow no-value user attributes which are automatically assigned "true"
when specified.
- Make "top" attribute string "true" instead of bool true for consistency.
Testing for existence is always enough for value-less attributes.
- Don't drop leading "_" from user attribute names when storing in dicts.
Dropping makes things more confusing.
- Add "_om_skip" to scx_layered fields which don't jive well with OM.
scxstats_to_openmetrics.py is updated accordignly and no longer generates
warnings on those fields.
- Examples and README updated accordingly.
This is a generic tool to pipe from scx_stats to OpenMetrics. This is a
barebone implmentation and the current output may not match what scx_layered
was outputting before. Will be updated later.
