how long wait_for_completion_interruptible_timeout() blocks

Subhashini Rao Beerisetty subhashbeerisetty at gmail.com
Thu Jun 20 03:28:16 EDT 2019


On Thu, Jun 20, 2019 at 11:38 AM anish singh
<anish198519851985 at gmail.com> wrote:
>
>
>
> On Wed, Jun 19, 2019 at 10:47 PM Subhashini Rao Beerisetty <subhashbeerisetty at gmail.com> wrote:
>>
>> Hi All,
>>
>> I’ve two Linux systems, I tried to measure how long
>> wait_for_completion_interruptible_timeout() blocked after completion
>> is signaled by complete() call. I noticed two different results in
>> both systems.
>>
>> In one system I noticed this duration in between 10 to 60 micro
>> seconds, where as in other system  it is in between 20 to 500 micro
>> seconds. I’d like to know what factors can affect this latency? Also,
>> is there any solution to reduce this latency?
>
>
> This is a problem which is fixed by RT Linux patches.
Can these patches be applied to Linux kernel source? If so can you
please give more information on this... where to find these patches?

> It is taking time as Linux is not RTOS and scheduler took time to put your task in running state which is expected and depends on many factors: such as load, interrupts and so on.
>>
>>
>>
>>
>> Thanks,
>>
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