On Mon, Oct 14, 2024 at 11:11 AM Yafang Shao <laoar.shao@gmail.com> wrote:
>
> After enabling CONFIG_IRQ_TIME_ACCOUNTING to track IRQ pressure in our
> container environment, we encountered several user-visible behavioral
> changes:
>
> - Interrupted IRQ/softirq time is not accounted for in the cpuacct cgroup
>
> This breaks userspace applications that rely on CPU usage data from
> cgroups to monitor CPU pressure. This patchset resolves the issue by
> ensuring that IRQ/softirq time is accounted for in the cgroup of the
> interrupted tasks.
>
> - getrusage(2) does not include time interrupted by IRQ/softirq
>
> Some services use getrusage(2) to check if workloads are experiencing CPU
> pressure. Since IRQ/softirq time is no longer charged to task runtime,
> getrusage(2) can no longer reflect the CPU pressure caused by heavy
> interrupts.
>
> This patchset addresses the first issue, which is relatively
> straightforward. However, the second issue remains unresolved, as there
> might be debate over whether interrupted time should be considered part of
> a task’s usage. Nonetheless, it is important to report interrupted time to
> the user via some metric, though that is a separate discussion.
>
> Changes:
> v2->v3:
> - Add a helper account_irqtime() to avoid redundant code (Johannes)
>
> v1->v2: https://lore.kernel.org/cgroups/20241008061951.3980-1-laoar.shao@gmail.com/
> - Fix lockdep issues reported by kernel test robot <oliver.sang@intel.com>
>
> v1: https://lore.kernel.org/all/20240923090028.16368-1-laoar.shao@gmail.com/
>
> Yafang Shao (4):
> sched: Define sched_clock_irqtime as static key
> sched: Don't account irq time if sched_clock_irqtime is disabled
> sched, psi: Don't account irq time if sched_clock_irqtime is disabled
> sched: Fix cgroup irq accounting for CONFIG_IRQ_TIME_ACCOUNTING
>
> kernel/sched/core.c | 78 +++++++++++++++++++++++++++++-------------
> kernel/sched/cputime.c | 16 ++++-----
> kernel/sched/psi.c | 12 ++-----
> kernel/sched/sched.h | 1 +
> kernel/sched/stats.h | 7 ++--
> 5 files changed, 69 insertions(+), 45 deletions(-)
>
> --
> 2.43.5
>
Hello Peter, Hello Ingo,
Do you have comments or any suggestions on this fix?
--
Regards
Yafang