[EXT] Re: [dpdk-stable] [PATCH v2] test: avoid hang if queues are full and Tx fails

[Thomas Monjalon]

22/11/2021 08:59, Rakesh Kudurumalla:
> From: Thomas Monjalon <thomas at monjalon.net>
> > 20/07/2021 18:50, Rakesh Kudurumalla:
> > > Current pmd_perf_autotest() in continuous mode tries to enqueue
> > > MAX_TRAFFIC_BURST completely before starting the test. Some drivers
> > > cannot accept complete MAX_TRAFFIC_BURST even though rx+tx desc
> > count
> > > can fit it.
> > 
> > Which driver is failing to do so?
> > Why it cannot enqueue 32 packets?
> 
> Octeontx2 driver is failing to enqueue because hardware buffers are full before test.

Why hardware buffers are full?

> pmd_perf_autotest() in continuous mode tries to enqueue MAX_TRAFFIC_BURST (2048)
> before starting the test.
> 
> > > This patch changes behaviour to stop enqueuing after few retries.
> > 
> > If there is a real limitation, there will be issues in more places than this test
> > program.
> > I feel it should be addressed either in the driver or at ethdev level.
> > 
> > [...]
> > > @@ -480,10 +483,19 @@ main_loop(__rte_unused void *args)
> > >  			nb_tx = RTE_MIN(MAX_PKT_BURST, num);
> > >  			nb_tx = rte_eth_tx_burst(portid, 0,
> > >  						&tx_burst[idx], nb_tx);
> > > +			if (nb_tx == 0)
> > > +				retry_cnt++;
> > >  			num -= nb_tx;
> > >  			idx += nb_tx;
> > > +			if (retry_cnt == MAX_RETRY_COUNT) {
> > > +				retry_cnt = 0;
> > > +				break;
> > > +			}