From: Stephen Hemminger <stephen@networkplumber.org>
To: Antonio Di Bacco <a.dibacco.ks@gmail.com>
Cc: "Gábor LENCSE" <lencse@hit.bme.hu>, users@dpdk.org
Subject: Re: rte_eth_tx_burst() always returns 0 in tight loop
Date: Wed, 6 Jul 2022 08:00:01 -0700 [thread overview]
Message-ID: <20220706080001.38ae3781@hermes.local> (raw)
In-Reply-To: <CAO8pfFmv=f9+fGq26Vt5+t6WnaRV3YXu10_F=7mBoj50AphpdQ@mail.gmail.com>
On Wed, 6 Jul 2022 09:21:28 +0200
Antonio Di Bacco <a.dibacco.ks@gmail.com> wrote:
> I wonder why calling eth_dev_tx_burst in a tight loop doesn't allow to
> write the packets into the transmit buffer. Only solution I found is
> to include a small delay after the tx_burst that is less than the
> estimated serialization time of the packet in order to be able to
> saturate the ethernet line.
>
> Anyway I wonder if this is the right approach.
>
> Thx,
> Antonio.
>
> On Sun, Jul 3, 2022 at 10:19 PM Gábor LENCSE <lencse@hit.bme.hu> wrote:
> >
> > Dear Antonio,
> >
> > According to my experience, the rte_eth_tx_burst() function reports the
> > packets as "sent" (by a non-zero return value), when they are still in
> > the transmit buffer.
> >
> > (If you are interested in the details, you can see them in Section 3.6.5
> > of this paper: http://www.hit.bme.hu/~lencse/publications/e104-b_2_128.pdf )
> >
> > Therefore, I think that the return value of 0 may mean that
> > rte_eth_tx_burst() can't even commit itself for the future delivery of
> > the packets. I could only guess why. E.g. all its resources have been
> > exhausted.
> >
> > Best regards,
> >
> > Gábor
> >
> >
> > 7/3/2022 5:57 PM keltezéssel, Antonio Di Bacco írta:
> > > I'm trying to send packets continuously in a tight loop with a burst
> > > size of 8 and packets are 9600 bytes long.
> > > If I don't insert a delay after the rte_eth_tx_burst it always returns 0.
> > >
> > > What's the explanation of this behaviour ?
> > >
> > > Best regards,
> > > Antonio.
> >
Which driver? How did you set the tx_free threshold.
The driver will need to cleanup already transmitted packets.
next prev parent reply other threads:[~2022-07-06 15:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-03 15:57 Antonio Di Bacco
2022-07-03 20:18 ` Gábor LENCSE
2022-07-06 7:21 ` Antonio Di Bacco
2022-07-06 15:00 ` Stephen Hemminger [this message]
2022-07-07 14:30 ` Antonio Di Bacco
2022-09-26 15:36 ` Antonio Di Bacco
2022-09-26 17:24 ` Stephen Hemminger
2022-07-06 15:03 ` Gábor LENCSE
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