[dpdk-users] Why DPDK latency is high when sending message in interval?

Vincenzo Maffione v.maffione at gmail.com
Mon Oct 29 16:25:52 CET 2018


Right, indeed the timerslack (50us) is not added if the process is
real-time.
But the C-state problem can still hit you hard.

Cheers,
  Vincenzo

Il giorno lun 29 ott 2018 alle ore 16:23 Stephen Hemminger <
stephen at networkplumber.org> ha scritto:

> On Sun, 28 Oct 2018 09:07:02 +0100
> Vincenzo Maffione <v.maffione at gmail.com> wrote:
>
> > If you don't care about CPU utilization, busy-wait is the way to go.
> > Otherwise you can try to usleep() for something like 60-70 us (to lower
> the
> > CPU utilization), and then busy-wait for the rest of the interval (so
> that
> > you still have maximum precision).
> >
> > You may want to have a look at this
> > https://academic.oup.com/comjnl/article/61/6/808/4259797 , specially
> > sections 4.3 and 4.1.
> >
> > Cheers,
> >   Vincenzo
> >
> > Il giorno dom 28 ott 2018 alle ore 09:01 Sungho Hong <
> > maverickjin88 at gmail.com> ha scritto:
> >
> > > Thank you very much for the reply.
> > > But in that case, should I busy wait, to create the delay?
> > >
> > >
> > >
> >
>
> If doing very brief and exact sleep, you should change your thread
> priority to
> one of the Real Time classes.
>


-- 
Vincenzo


More information about the users mailing list