Add scx scheduler options support

[shelterx]

Perhaps it's too complex for kervers purpose, I don't know. But it seems to work, I tested it with several schedulers.

[sirlucjan]

❯ kerver
Check kernel version:

Linux version 6.16.4-1.1-cachyos (linux-cachyos@cachyos) (clang version 20.1.8, LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC Thu, 28 Aug 2025 17:23:09 +0000
Linux cachyos 6.16.4-1.1-cachyos #1 SMP PREEMPT_DYNAMIC Thu, 28 Aug 2025 17:23:09 +0000 x86_64 GNU/Linux


Check x86_64 support:

  x86-64-v4 (supported, searched)
  x86-64-v3 (supported, searched)
  x86-64-v2 (supported, searched)


Check CPU config:

# CONFIG_X86_NATIVE_CPU is not set
# CONFIG_GENERIC_CPU is not set
CONFIG_MZEN4=y

Check some configuration variables:

CONFIG_SCHED_CLASS_EXT=y
CONFIG_LTO_CLANG=y
# CONFIG_LTO_CLANG_FULL is not set
# CONFIG_LTO_CLANG_THIN is not set
CONFIG_LTO_CLANG_THIN_DIST=y
CONFIG_AUTOFDO_CLANG=y
CONFIG_PROPELLER_CLANG=y

Current disk schedulers:

nvme0n1: [none] mq-deadline kyber adios bfq 

Check available schedulers:

sie 29 07:48:23 cachyos kernel: BORE CPU Scheduler modification 6.5.2 by Masahito Suzuki
sie 29 07:48:23 cachyos kernel: rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies.
sie 29 07:48:23 cachyos kernel: Transient Scheduler Attacks: Mitigation: Clear CPU buffers
sie 29 07:48:23 cachyos kernel: io scheduler mq-deadline registered
sie 29 07:48:23 cachyos kernel: io scheduler kyber registered
sie 29 07:48:23 cachyos kernel: Adaptive Deadline I/O Scheduler 3.0.1 by Masahito Suzuki
sie 29 07:48:23 cachyos kernel: io scheduler adios registered
sie 29 07:48:23 cachyos kernel: io scheduler bfq registered
sie 29 11:55:41 cachyos kernel: sched_ext: BPF scheduler "flash_1.0.13_g3c6fb461_dirty_x86_64_unknown_linux_gnu" enabled with options -m performance -D -L
lucjan at cachyos ~ 11:55:44    

I have slightly different output, but in principle it works correctly.

[shelterx]

A much simpler approach would be to use scxctl, it would probably reduce the complexity a bit. I just stumbled upon it...

$ scxctl get
running Flash with arguments "-m all -s 2000 -S 200 -I 16 -n -w"

I'll have a look at that when I get the time.
I think it's best trying to preserve the version of the scx scheduler tho'

UPDATE:
I'll keep this the way it is for now since it's a more universal approach and does not rely on scx-manager.

[sirlucjan]

sched-ext/scx#2769

@shelterx I think that we could try scxctl with next release (1.0.17).

[shelterx]

@sirlucjan I can make an alternative PR and if that looka good we can ditch this one. I like the universal aspect of this one though.

[sirlucjan]

All in all, you're right, leave it as it is.