From: Vincenzo Maffione <v.maffione@gmail.com>
To: stephen@networkplumber.org
Cc: Sungho Hong <maverickjin88@gmail.com>, users@dpdk.org
Subject: Re: [dpdk-users] Why DPDK latency is high when sending message in interval?
Date: Mon, 29 Oct 2018 16:25:52 +0100 [thread overview]
Message-ID: <CA+_eA9ggyAjUETrZWv+WY2uE-dVhVPxSa-136yRB4B3WdkA6Cw@mail.gmail.com> (raw)
In-Reply-To: <20181029082339.15d4ebee@xeon-e3>
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@networkplumber.org> ha scritto:
> On Sun, 28 Oct 2018 09:07:02 +0100
> Vincenzo Maffione <v.maffione@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@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
next prev parent reply other threads:[~2018-10-29 15:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-27 23:36 Sungho Hong
2018-10-28 7:53 ` Vincenzo Maffione
2018-10-28 8:01 ` Sungho Hong
2018-10-28 8:07 ` Vincenzo Maffione
2018-10-28 10:15 ` Sungho Hong
2018-10-29 15:23 ` Stephen Hemminger
2018-10-29 15:25 ` Vincenzo Maffione [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-10-26 20:37 Sungho Hong
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