Messages in this thread | | | Subject | Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism | From | Daniel Lezcano <> | Date | Wed, 4 Sep 2019 19:31:48 +0200 |
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Hi,
On 04/09/2019 19:07, Bart Van Assche wrote: > On 9/3/19 12:50 AM, Daniel Lezcano wrote: >> On 03/09/2019 09:28, Ming Lei wrote: >>> On Tue, Sep 03, 2019 at 08:40:35AM +0200, Daniel Lezcano wrote: >>>> It is a scheduler problem then ? >>> >>> Scheduler can do nothing if the CPU is taken completely by handling >>> interrupt & softirq, so seems not a scheduler problem, IMO. >> >> Why? If there is a irq pressure on one CPU reducing its capacity, the >> scheduler will balance the tasks on another CPU, no? > > Only if CONFIG_IRQ_TIME_ACCOUNTING has been enabled. However, I don't > know any Linux distro that enables that option. That's probably because > that option introduces two rdtsc() calls in each interrupt. Given the > overhead introduced by this option, I don't think this is the solution > Ming is looking for.
Was this overhead reported somewhere ?
> See also irqtime_account_irq() in kernel/sched/cputime.c.
From my POV, this framework could be interesting to detect this situation.
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