As described in [0], there is an open problem in load balancing called
the "infeasible weights" problem. Essentially, the problem boils down to
the fact that a task with disproportionately high load can be granted
more CPU time than they can actually consume per their duty cycle.
This patch implements a solution to that problem, wherein we apply the
algorithm described in this paper to adjust all infeasible weights in
the system down to a feasible wight that gives them their full duty
cycle, while allowing the remaining feasible tasks on the system to
share the remaining compute capacity on the machine.
[0]: https://drive.google.com/file/d/1fAoWUlmW-HTp6akuATVpMxpUpvWcGSAv/view?usp=drive_link
Signed-off-by: David Vernet <void@manifault.com>
After updates to reflect the updated init and direct dispatch API, the
schedulers aren't compatible with older kernels. Bump versions and publish
releases.
In the latest kernel, sched_ext API has changed in two areas:
- ops.prep_enable/cancel_enable/enable/disable() replaced with
ops.init_task/enable/disable/exit_task().
- scx_bpf_dispatch() can now be called from ops.select_cpu(). Also,
SCX_ENQ_LOCAL flag is removed. Instead, users can call
scx_bpf_select_cpu_dfl() from ops.select_cpu() and use the @is_idle out
param value to determine whether to dispatch directly.
This commit updates all schedules so that they build.
- Init functions renamed / merged / split.
- ops.select_cpu() is added to several schedulers and local direct
disptching logic is moved there.
This is the minimum update which is need to make the schedulers build and
work. It needs further update to e.g. move vtime udpates to ops.enable().
This because each scheduler has it's own Rust Crate
and it's better if they had a README associated with each one.
https://crates.io/crates/scx_layered
- combine c and kernel-examples as it's confusing to have both
- rename 'rust-user' and 'c-user' to just 'rust' and 'c', which is simpler
- update and fix sync-to-kernel.sh
