Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism

Bart Van Assche
2019-09-04T17:39:03Z

On 9/4/19 10:31 AM, Daniel Lezcano wrote:
> On 04/09/2019 19:07, Bart Van Assche wrote:
>> 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 ?
I think it is widely known that rdtsc is a relatively slow x86
instruction. So I expect that using that instruction will cause a
measurable overhead if it is called frequently enough. I'm not aware of
any publicly available measurement data however.

Bart.