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. -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
