On 7/22/22 2:13 PM, Chengming Zhou Wrote:
On 2022/7/22 11:30, Abel Wu wrote:
Hi Chengming,
On 7/21/22 12:04 PM, Chengming Zhou Wrote:
Now PSI already tracked workload pressure stall information for
CPU, memory and IO. Apart from these, IRQ/SOFTIRQ could have
obvious impact on some workload productivity, such as web service
workload.
When CONFIG_IRQ_TIME_ACCOUNTING, we can get IRQ/SOFTIRQ delta time
from update_rq_clock_task(), in which we can record that delta
to CPU curr task's cgroups as PSI_IRQ_FULL status.
The {soft,}irq affection should be equal to all the runnable tasks
on that cpu, not only rq->curr. Further I think irqstall is per-cpu
rather than per-cgroup.
Although IRQ/SOFTIRQ is per-cpu, it's the rq->curr who own the CPU at the time
and pay for it, meanwhile other groups would be thought as PSI_CPU_FULL.
I don't think rq->curr pays for it if you mean consuming quota here.
And it doesn't seem appropriate to let other groups treat it as cpu
stall because the rq->curr is also the victim rather than the one
causes stall (so it's different from rq->curr causing memstall and
observed as cpustall by others).
So I think it's reasonable to account this IRQ/SOFTIRQ delta to rq->curr's groups
as PSI_IRQ_FULL pressure stall. And per-cpu IRQ stall can also get from psi_system.
