[dpdk-dev] [PATCH 2/6] testpmd: configurable tx_first burst number

Wang, Zhihong zhihong.wang at intel.com
Thu May 26 11:31:41 CEST 2016



> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> Sent: Thursday, May 26, 2016 2:32 PM
> To: Wang, Zhihong <zhihong.wang at intel.com>
> Cc: dev at dpdk.org; Ananyev, Konstantin <konstantin.ananyev at intel.com>;
> Richardson, Bruce <bruce.richardson at intel.com>; De Lara Guarch, Pablo
> <pablo.de.lara.guarch at intel.com>
> Subject: Re: [PATCH 2/6] testpmd: configurable tx_first burst number
> 
> 2016-05-26 02:53, Wang, Zhihong:
> > From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> > > 2016-05-05 18:46, Zhihong Wang:
> > > > This patch enables configurable tx_first burst number.
> > > >
> > > > Use "start tx_first (burst_num)" to specify how many bursts of packets to
> > > > be sent before forwarding start, or "start tx_first" like before for the
> > > > default 1 burst send.
> > >
> > > The idea here is to fill the loopback latency gap with bursts.
> > > Would it be possible to make it automatic by detecting the first
> > > received packets to stop Tx generator?
> >
> > The idea is great! The implementation might not be graceful though
> > -- current tx_first mode first calls txonly engine before calling the
> > actual engine, say iofwd, so iofwd is not established before tx_first
> > is done, therefore no detection.
> 
> And what about rewriting tx_first?
> No strong opinion. I let you and Pablo decide.
> 


I think the current way is better in terms of simplicity and flexibility.
Also this "fill the ring" criteria doesn't fit other test scenarios, it's
just for this loop back test, but tx_first is for all scenarios.


> > It's possible to do this, but we need to implement another forward
> > engine like "io_retry_fill_first" alone, it complicates testpmd just for
> > this loop back test.
> >
> > Looks to me it's better to use combination of existing fwd engines to
> > do this, it's also more flexible with burst number parameters.



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