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From: Bruce Richardson <bruce.richardson@intel.com>
To: Sachin Sharma <sharonsachin@gmail.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] transmit functions of dpdk
Date: Wed, 10 Dec 2014 11:45:17 +0000
Message-ID: <20141210114517.GD10056@bricha3-MOBL3> (raw)
In-Reply-To: <CAH-Vi3ysN=6dm8DweW9VnP4c66JVMDT6trSYBV0XaDwF0cf=vQ@mail.gmail.com>

On Wed, Dec 10, 2014 at 12:31:27PM +0100, Sachin Sharma wrote:
> Hi Bruce,
> 
> In my use case, I want to have three NIC TX queues per port, and want to
> fill one NIC TX queue and want to empty the other queue. Is it possible
> this through tx_burst or do I need to implement these queues in
> applications as you suggested before. However, in this case, I would have
> then one NIC TX queues and three queues in an application which actually
> transmits packets to this NIC TX queue. Am I right?
> 

For the suggestion I made, yes, you would have three software queues in your
application, and a single TX on the NIC - though you could also have a 1:1 mapping
of software to HW queues if you wanted.
However, I'm not entirely clear on what you mean by filling one queue and emptying
another. Is this just a form of buffering you are trying to implement?

> Thanks,
> Sachin.
> 
> On Wed, Dec 10, 2014 at 12:22 PM, Bruce Richardson <
> bruce.richardson@intel.com> wrote:
> 
> > On Wed, Dec 10, 2014 at 12:03:41PM +0100, Sachin Sharma wrote:
> > > Dear all,
> > >
> > >  In my algorithm, I am interested to perform  two activities - (1)
> > > transmitting packets to a tx_queue and (2) transmitting packets from
> > > tx_queue to a wire - separately. I have gone through the code by putting
> > > logs in the dpdk code and found that there is a function rte_eth_tx_burst
> > > which transmits packets to a specific queue. However, when I debugged
> > more
> > > then I found that this function just calls eth_igb_xmit_pkts
> > > from librte_pmd_e1000, and this function just directly write the packets
> > to
> > > the wire by writing all packets into registers. Could you please suggest
> > > how to implement these two functions if these are not implemented already
> > > in dpdk?
> > >
> > >
> > >
> > > Thanks & Regards,
> > > Sachin.
> >
> > Hi Sachin,
> >
> > anything written to the NIC TX queue is automatically put onto the wire
> > unless
> > the NIC port is down or the wire is unplugged etc. What is your use-case
> > that you
> > need to do this? I would suggest doing internal buffering in your
> > application,
> > as many DPDK example applications do, and then call tx_burst to put your
> > packets
> > on the wire when you want this capability.
> >
> > Regards,
> > /Bruce
> >

  reply	other threads:[~2014-12-10 11:45 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-10 11:03 Sachin Sharma
2014-12-10 11:22 ` Bruce Richardson
2014-12-10 11:31   ` Sachin Sharma
2014-12-10 11:45     ` Bruce Richardson [this message]
2014-12-10 12:09       ` Sachin Sharma
2014-12-10 13:37         ` Bruce Richardson
2014-12-10 14:14           ` Sachin Sharma

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