[Devel] [PATCH vz10 v4 0/3] Clean up vCPU handling code

[Pavel Tikhomirov]

Reviewed-by: Pavel Tikhomirov <ptikhomirov at virtuozzo.com>

On 3/19/26 10:47, Dmitry Sepp wrote:
> The idea behind the change is to transition from the existing spatial
> vCPU handling approach that introduces costly modification to the
> scheduling logic to ensure the requested CPU count is obeyed (10%+
> performance drop in some tests, see below) to temporal isolation that can be
> provided by the cgroup2 cpu.max.
> 
> Reference test results:
> 
> 1. Clean setup, no vCPU related modifications:
> ~/at_process_ctxswitch_pipe -w -p 2 -t 15
> rate_total: 856509.625000, avg: 428254.812500
> 
> 2. vCPU related modifications (present state):
> ~/at_process_ctxswitch_pipe -w -p 2 -t 15
> rate_total: 735626.812500, avg: 367813.406250
> 
> 3. Cleaned-up vCPU handling:
> ~/at_process_ctxswitch_pipe -w -p 2 -t 15
> rate_total: 840074.750000, avg: 420037.375000
> 
> Changes in v4:
>  - While at it, fix a locking issue in tg_set_cpu_limit()
> 
> 
> Dmitry Sepp (3):
>   sched: Clean up vCPU handling logic
>   sched: Support nr_cpus in cgroup2 as well
>   sched: Add missing cpus_read_lock() in tg_set_cpu_limit()
> 
>  include/linux/sched.h          |   6 -
>  include/linux/sched/topology.h |   5 -
>  kernel/sched/core.c            | 108 ++-------
>  kernel/sched/fair.c            | 408 ---------------------------------
>  kernel/sched/sched.h           |  10 -
>  5 files changed, 22 insertions(+), 515 deletions(-)
> 
> 
> base-commit: 9dc72d17b6abbe7353f01f6ac44551f75299a560

-- 
Best regards, Pavel Tikhomirov
Senior Software Developer, Virtuozzo.