strange response time question

Yuxin Ren ryx at
Tue Aug 5 23:19:09 CEST 2014


Sorry, it's my typo.
The worse case is 200us.
In my test, before the client sends IPC, I record the time using rdtsc.
When the server receives this IPC, I also do rdtsc.
The difference between this is the response time. I run this many
iterations and the maximum value is the worse case result.
I filter out the timer interrupt, but do not flush the cache and tlb.

Thank you very much,

On Tue, Aug 5, 2014 at 4:41 PM, Adam Lackorzynski <adam at
> wrote:

> On Tue Aug 05, 2014 at 13:03:51 -0400, Yuxin Ren wrote:
> > Now I am testing the response time in Fiasco, especially for the worse
> case.
> > The results are strange.
> > The worse case result are always around 2us.
> > I have filtered out the timer interrupt, so I cannot understand what
> > happened.
> > I am using intel IA32 multi core cpu.
> > Do you have any idea about what can cause the 2us delay?
> For worst case, 2µs does not seem bad to me for this type of CPU. How
> did you try to get the worst case (or do you mean something different
> with 'worse case'?)?
> Adam
> --
> Adam                 adam at
>   Lackorzynski
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