Re: [PATCH 0/4] tools/sched_ext: Add example C schedulers

[Andrea Righi <arighi@nvidia.com>]

On Tue, Jan 13, 2026 at 02:57:13PM +0900, Changwoo Min wrote:
> Hi Emil,
> 
> On 1/13/26 6:41 AM, Emil Tsalapatis wrote:
> > Add to the tree several C sched-ext schedulers developed and maintained
> > out-of-tree by the sched-ext project over the years. These schedulers
> > demonstrate sched-ext's feature set and provide a starting point for
> > scheduler development. Place the schedulers together with the existing
> > examples in tools/sched_ext.
> 
> In general, I am okay to include more examples of C schedulers in the
> kernel tree. However, I am doubtful whether it is worth including the
> nest scheduler, as it has been barely maintained in recent times.

+1 on that, even if it's a good example, it's still unmaintained code.
Maybe we should just move it in a separate github repo.

For the rest of the schedulers I'm ok to include them in-tree (still under
the assumption that they should be considered examples).

Thanks,
-Andrea

> 
> Regards,
> Changwoo Min
> 
> > 
> > Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
> > 
> > Emil Tsalapatis (4):
> >    tools/sched_ext: add scx_nest scheduler
> >    tools/sched_ext: add scx_userland scheduler
> >    tools/sched_ext: add scx_pair scheduler
> >    tools/sched_ext: add arena based scheduler
> > 
> >   tools/sched_ext/Makefile               |   2 +-
> >   tools/sched_ext/scx_nest.bpf.c         | 652 +++++++++++++++++++++++
> >   tools/sched_ext/scx_nest.c             | 240 +++++++++
> >   tools/sched_ext/scx_nest.h             |  18 +
> >   tools/sched_ext/scx_nest_stats_table.h |  20 +
> >   tools/sched_ext/scx_pair.bpf.c         | 610 +++++++++++++++++++++
> >   tools/sched_ext/scx_pair.c             | 180 +++++++
> >   tools/sched_ext/scx_pair.h             |   9 +
> >   tools/sched_ext/scx_sdt.bpf.c          | 710 +++++++++++++++++++++++++
> >   tools/sched_ext/scx_sdt.c              | 101 ++++
> >   tools/sched_ext/scx_sdt.h              | 113 ++++
> >   tools/sched_ext/scx_userland.bpf.c     | 344 ++++++++++++
> >   tools/sched_ext/scx_userland.c         | 437 +++++++++++++++
> >   tools/sched_ext/scx_userland.h         |  17 +
> >   14 files changed, 3452 insertions(+), 1 deletion(-)
> >   create mode 100644 tools/sched_ext/scx_nest.bpf.c
> >   create mode 100644 tools/sched_ext/scx_nest.c
> >   create mode 100644 tools/sched_ext/scx_nest.h
> >   create mode 100644 tools/sched_ext/scx_nest_stats_table.h
> >   create mode 100644 tools/sched_ext/scx_pair.bpf.c
> >   create mode 100644 tools/sched_ext/scx_pair.c
> >   create mode 100644 tools/sched_ext/scx_pair.h
> >   create mode 100644 tools/sched_ext/scx_sdt.bpf.c
> >   create mode 100644 tools/sched_ext/scx_sdt.c
> >   create mode 100644 tools/sched_ext/scx_sdt.h
> >   create mode 100644 tools/sched_ext/scx_userland.bpf.c
> >   create mode 100644 tools/sched_ext/scx_userland.c
> >   create mode 100644 tools/sched_ext/scx_userland.h
> > 
>