RE: [PATCH] app/testpmd: skip stopped queues when forwarding

["Zhang, Yuying" <yuying.zhang@intel.com>]

Hi Dmitry,

> -----Original Message-----
> From: Singh, Aman Deep <aman.deep.singh@intel.com>
> Sent: Thursday, February 3, 2022 9:52 PM
> To: Dmitry Kozlyuk <dkozlyuk@nvidia.com>; dev@dpdk.org
> Cc: Li, Xiaoyun <xiaoyun.li@intel.com>; Zhang, Yuying
> <yuying.zhang@intel.com>; jing.d.chen@intel.com; stable@dpdk.org; Raslan
> Darawsheh <rasland@nvidia.com>
> Subject: Re: [PATCH] app/testpmd: skip stopped queues when forwarding
> 
> Hi Dmitry,
> 
> Thanks for the patch.
> 
> On 1/13/2022 2:51 PM, Dmitry Kozlyuk wrote:
> > After "port <port_id> rxq|txq <queue_id> stop"
> > the stopped queue was used in forwarding nonetheless, which may cause
> > undefined behavior in the PMD.
> >
> > Record the configured queue state
> > and account for it when launching forwarding as follows:
> > +--------+---------+-----------------+---------------+
> > |RxQ     |TxQ      |Configured mode  |Launch routine |
> > +--------+---------+-----------------+---------------+
> > |stopped |stopped  |*                |-              |
> > |stopped |started  |txonly           |(configured)   |
> > |stopped |started  |*                |-              |
> > |started |stopped  |*                |rxonly         |
> > |started |started  |*                |(configured)   |
> > +--------+---------+-----------------+---------------+
> > Display stopped queues on "show port config rxtx".
> >
> > Fixes: 5f4ec54f1d16 ("testpmd: queue start and stop")
> > Cc: jing.d.chen@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
> > Reviewed-by: Raslan Darawsheh <rasland@nvidia.com>
> > ---
> >   app/test-pmd/cmdline.c |  8 ++++++++
> >   app/test-pmd/config.c  |  6 ++++++
> >   app/test-pmd/testpmd.c | 18 ++++++++++++++++--
> >   app/test-pmd/testpmd.h | 10 ++++++++++
> >   4 files changed, 40 insertions(+), 2 deletions(-)
> >
> > diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c index
> > e626b1c7d9..8b0920e23d 100644
> > --- a/app/test-pmd/cmdline.c
> > +++ b/app/test-pmd/cmdline.c
> > @@ -2702,6 +2702,14 @@ cmd_config_rxtx_queue_parsed(void
> > *parsed_result,
> >
> >   	if (ret == -ENOTSUP)
> >   		fprintf(stderr, "Function not supported in PMD\n");
> > +	if (ret == 0) {
> > +		struct rte_port *port;
> > +		struct queue_state *states;
> > +
> > +		port = &ports[res->portid];
> > +		states = isrx ? port->rxq_state : port->txq_state;
> > +		states[res->qid].stopped = !isstart;
> > +	}
> >   }
> >
> >   cmdline_parse_token_string_t cmd_config_rxtx_queue_port = diff --git
> > a/app/test-pmd/config.c b/app/test-pmd/config.c index
> > 1722d6c8f8..7ce9cb483a 100644
> > --- a/app/test-pmd/config.c
> > +++ b/app/test-pmd/config.c
> > @@ -2817,6 +2817,9 @@ rxtx_config_display(void)
> >   				       rx_conf->share_qid);
> >   			printf("\n");
> >   		}
> > +		for (qid = 0; qid < nb_rxq; qid++)
> > +			if (ports[pid].rxq_state[qid].stopped)
> > +				printf("    RX queue %d is stopped\n", qid);
> >
> >   		/* per tx queue config only for first queue to be less verbose
> */
> >   		for (qid = 0; qid < 1; qid++) {
> > @@ -2850,6 +2853,9 @@ rxtx_config_display(void)
> >   			printf("      TX offloads=0x%"PRIx64" - TX RS bit
> threshold=%d\n",
> >   				offloads_tmp, tx_rs_thresh_tmp);
> >   		}
> > +		for (qid = 0; qid < nb_txq; qid++)
> > +			if (ports[pid].txq_state[qid].stopped)
> > +				printf("    TX queue %d is stopped\n", qid);
> >   	}
> >   }
> >
> > diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c index
> > 6c387bde84..36ff845181 100644
> > --- a/app/test-pmd/testpmd.c
> > +++ b/app/test-pmd/testpmd.c
> > @@ -2152,6 +2152,8 @@ flush_fwd_rx_queues(void)
> >   		for (rxp = 0; rxp < cur_fwd_config.nb_fwd_ports; rxp++) {
> >   			for (rxq = 0; rxq < nb_rxq; rxq++) {
> >   				port_id = fwd_ports_ids[rxp];
> > +				if (ports[port_id].rxq_state[rxq].stopped)
> > +					continue;
> >   				/**
> >   				* testpmd can stuck in the below do while
> loop
> >   				* if rte_eth_rx_burst() always returns
> nonzero @@ -2223,8
> > +2225,20 @@ run_pkt_fwd_on_lcore(struct fwd_lcore *fc, packet_fwd_t
> pkt_fwd)
> >   static int
> >   start_pkt_forward_on_core(void *fwd_arg)
> >   {
> > -	run_pkt_fwd_on_lcore((struct fwd_lcore *) fwd_arg,
> > -			     cur_fwd_config.fwd_eng->packet_fwd);
> > +	struct fwd_lcore *fc = fwd_arg;
> > +	struct fwd_stream *fsm = fwd_streams[fc->stream_idx];
> > +	struct queue_state *rxq = &ports[fsm->rx_port].rxq_state[fsm-
> >rx_queue];
> > +	struct queue_state *txq = &ports[fsm->tx_port].txq_state[fsm-
> >tx_queue];
> > +	struct fwd_engine *fwd_engine = cur_fwd_config.fwd_eng;
> > +	packet_fwd_t packet_fwd;
> > +
> > +	/* Check if there will ever be any packets to send. */
> > +	if (rxq->stopped && (txq->stopped || fwd_engine !=
> &tx_only_engine))
> > +		return 0;
Have you considered other fwd_engines such as io_fwd_engine and mac_fwd_engine?
> > +	/* Force rxonly mode if RxQ is started, but TxQ is stopped. */
> > +	packet_fwd = !rxq->stopped && txq->stopped ?
> rx_only_engine.packet_fwd
> > +						   : fwd_engine->packet_fwd;
> Should we have a print here for user info, that mode has been changed or
> ignored.
Why need to force rxonly mode for this situation? BTW, the value of cur_fwd_eng
hasn't been updated after you changed forward mode.
> > +	run_pkt_fwd_on_lcore(fc, packet_fwd);
> >   	return 0;
> >   }
> >
> > diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h index
> > 2149ecd93a..2744fa4d76 100644
> > --- a/app/test-pmd/testpmd.h
> > +++ b/app/test-pmd/testpmd.h
> > @@ -216,6 +216,12 @@ struct xstat_display_info {
> >   	bool	 allocated;
> >   };
> >
> > +/** Application state of a queue. */
> > +struct queue_state {
> > +	/** The queue is stopped and should not be used. */
> > +	bool stopped;
> > +};
> > +
> >   /**
> >    * The data structure associated with each port.
> >    */
> > @@ -256,6 +262,10 @@ struct rte_port {
> >   	uint64_t		mbuf_dynf;
> >   	const struct rte_eth_rxtx_callback
> *tx_set_dynf_cb[RTE_MAX_QUEUES_PER_PORT+1];
> >   	struct xstat_display_info xstats_info;
> > +	/** Per-Rx-queue state. */
> > +	struct queue_state rxq_state[RTE_MAX_QUEUES_PER_PORT];
> > +	/** Per-Tx-queue state. */
> > +	struct queue_state txq_state[RTE_MAX_QUEUES_PER_PORT];
> Can we think of adding rxq_state/txq_state as part of existing structures
> under rte_port->rte_eth_rxconf/rte_eth_txconf.
> And if it helps, rather than bool can we use u8 with eth_dev defines- #define
> RTE_ETH_QUEUE_STATE_STOPPED 0 /**< Queue stopped. */ #define
> RTE_ETH_QUEUE_STATE_STARTED 1 /**< Queue started. */
The same.
> >   };
> >
> >   /**