Re: [PATCH v5 7/7] sched/fair: Fair server interface

[Joel Fernandes <joel@joelfernandes.org>]

On 2/12/2024 9:13 PM, Joel Fernandes wrote:
> 
> 
> On 11/4/2023 6:59 AM, Daniel Bristot de Oliveira wrote:
>> Add an interface for fair server setup on debugfs.
>>
>> Each rq have three files under /sys/kernel/debug/sched/rq/CPU{ID}:
>>
>>  - fair_server_runtime: set runtime in ns
>>  - fair_server_period: set period in ns
>>  - fair_server_defer: on/off for the defer mechanism
> 
> Btw Daniel, there is an interesting side-effect of this interface having runtime
> and period in 2 separate files :)
> 
> Say I want to set a CPU to 5ms / 10ms.
> 

Sorry let me try again, say I want to set 500us / 1ms.

Then I have to do the following to get it to work:

# echo 100000000 > /sys/kernel/debug/sched/fair_server/cpu0/period
# echo 5000000 > /sys/kernel/debug/sched/fair_server/cpu0/runtime
# echo 10000000 > /sys/kernel/debug/sched/fair_server/cpu0/period
# echo 500000 > /sys/kernel/debug/sched/fair_server/cpu0/runtime
# echo 1000000 > /sys/kernel/debug/sched/fair_server/cpu0/period

IOW, if I boot and do the following, it fails:

# echo 500000 > /sys/kernel/debug/sched/fair_server/cpu0/runtime
bash: echo: write error: Device or resource busy

 - Joel