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

[Rakesh Kudurumalla <rkudurumalla@marvell.com>]

Octeontx2 driver is failing to enqueue because hardware buffers are full before test.
pmd_perf_autotest() in continuous mode tries to enqueue MAX_TRAFFIC_BURST (2048)
before starting the test.

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Friday, November 12, 2021 5:02 PM
> To: Rakesh Kudurumalla <rkudurumalla@marvell.com>
> Cc: stable@dpdk.org; dev@dpdk.org; david.marchand@redhat.com;
> ferruh.yigit@intel.com; andrew.rybchenko@oktetlabs.ru;
> ajit.khaparde@broadcom.com; Jerin Jacob Kollanukkaran
> <jerinj@marvell.com>
> Subject: [EXT] Re: [dpdk-stable] [PATCH v2] test: avoid hang if queues are full
> and Tx fails
> 
> External Email
> 
> ----------------------------------------------------------------------
> 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?
> 
> > 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;
> > +			}
> 
>