Re: [dpdk-dev] ixgbe vector mode not working.

["Liang, Cunming" <cunming.liang@intel.com>]

Hi Stephen,

Thanks for the info, with rxd=4000, I can reproduce it.
On that time, it runs out of mbuf.
I'll follow up this issue.

> -----Original Message-----
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Wednesday, February 25, 2015 3:37 PM
> To: Liang, Cunming
> Cc: Nemeth, Balazs; Richardson, Bruce; Neil Horman; dev@dpdk.org
> Subject: Re: ixgbe vector mode not working.
> 
> On Wed, 25 Feb 2015 04:55:09 +0000
> "Liang, Cunming" <cunming.liang@intel.com> wrote:
> 
> > Hi Stephen,
> >
> > I tried on the latest mater branch with testpmd.
> > 2 rxq and 2 txq as below, vector pmd on both rx and tx. I can't reproduced it.
> > I checked your log, on tx side, it looks the tx vector haven't enabled. (it shows
> vpmd on rx, spmd on tx).
> > Would you help to share the below params in your app ?
> > 	RX desc=128 - RX free threshold=32
> > 	TX desc=512 - TX free threshold=32
> > 	TX RS bit threshold=32 - TXQ flags=0xf01
> > As in your case which using 2 rxq and 1 txq, would you explain the traffic flow
> between them.
> > One thread polling packets from each rxq and send to the specified txq ?
> 
> Basic thread model of application is same as examples/qos_sched.
> 
> On ixgbe:
> 	RX desc = 4000 - RX free threshold=32
> 	TX desc = 512  - TX free threshold=0 so driver sets default of 32
> 
> I was setting rx/tx conf but since examples don't went away from that.

[LCM] All these params defined in rte_eth_rxconf/rte_eth_txconf which are used during rte_eth_rx/tx_queue_setup.
If don't care the value and assign nothing for it, it takes the default value per each device.
For ixgbe, the default_txconf will use the vpmd. In your log, it's not. So that's why I asked for such params.

> 
> The whole RX/TX tuning parameters are a very poor programming model only
> a hardware engineer could love. Requiring the application to look at
> driver string and choose the magic parameter settings, is in my opnion
> an indication of using incorrect abstraction.
[LCM] It's not necessary for application to look at such parameter. As you said, that's only for RX/TX tuning.
If tuning, it makes sense to understand what these parameters mean.