[Question] Sched: Severe scheduling latency (>10s) observed on kernel 6.12 with specific workload

[Xuewen Yan]

Dear Linux maintainers and reviewers,

I am writing to report a severe scheduling latency issue we recently
discovered on Linux Kernel 6.12.

Issue Description

We observed that when running a specific background workload pattern,
certain tasks experience excessive scheduling latency. The delay from
the runnable state to running on the CPU exceeds 10 seconds, and in
extreme cases, it reaches up to 100 seconds.

Environment Details

Kernel Version: 6.12.58-android16-6-g3835fd28159d-ab000018-4k
Architecture: [ ARM64]
Hardware: T7300
Config: gki_defconfig

RT-app‘s workload Pattern:

{
    "tasks" : {
            "t0" : {
                    "instance" : 40,
                    "priority" : 0,
                    "cpus" : [ 0, 1, 2, 3 ],
"taskgroup" : "/background",
                    "loop" : -1,
                    "run" : 200,
                    "sleep" : 50
            }
    }
}

And we have applied the following patchs:

https://lore.kernel.org/all/20251216111321.966709786@xxxxxxxxxxxxxxxxxxx/
https://lore.kernel.org/all/20260106170509.413636243@xxxxxxxxxxxxxxxxxxx/
https://lore.kernel.org/all/20260323134533.805879358@xxxxxxxxxxxxxxxxxxx/


Could you please advise if there are known changes in the eevdf in
6.12 that might affect this specific workload pattern?

Thanks!

BR
---
xuewen

Attachment: eevdf_debug.json
Description: application/json

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