Re: [dpdk-dev] [PATCH v2] eventdev: fix Rx adapter event flush logic

["Rao, Nikhil" <nikhil.rao@intel.com>]

> -----Original Message-----
> From: Mattias Rönnblom [mailto:mattias.ronnblom@ericsson.com]
> Sent: Friday, May 10, 2019 12:52 AM
> To: Rao, Nikhil <nikhil.rao@intel.com>; jerinj@marvell.com
> Cc: dev@dpdk.org; matias.elo@nokia.com
> Subject: Re: [dpdk-dev] [PATCH v2] eventdev: fix Rx adapter event flush logic
> 
> On 2019-05-09 06:50, Nikhil Rao wrote:
> > The Rx adapter flushes events only if it has BATCH_SIZE events
> > buffered where BATCH_SIZE is set to 32, e.g., if a single packet is
> > sent, it is never passed to eventdev. Fix this issue by adding an
> > event buffer flush either when a Rx queue is found to be empty or the
> > adapter service function has processed the max number of packets for
> > an invocation.
> >
> > Bugzilla ID: 277
> >
> > Fixes: 6b83f5935543 ("eventdev: add event buffer flush in Rx adapter")
> >
> > Reported-by: Matias Elo <matias.elo@nokia.com>
> >
> > Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
> > ---
> >   lib/librte_eventdev/rte_event_eth_rx_adapter.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > v2:
> > * added Bugzilla ID
> >
> > diff --git a/lib/librte_eventdev/rte_event_eth_rx_adapter.c
> > b/lib/librte_eventdev/rte_event_eth_rx_adapter.c
> > index 8d178be..fd3761b 100644
> > --- a/lib/librte_eventdev/rte_event_eth_rx_adapter.c
> > +++ b/lib/librte_eventdev/rte_event_eth_rx_adapter.c
> > @@ -872,7 +872,7 @@ static uint16_t rxa_gcd_u16(uint16_t a, uint16_t b)
> >   			break;
> >   	}
> >
> > -	if (buf->count >= BATCH_SIZE)
> > +	if (buf->count)
> >   		rxa_flush_event_buffer(rx_adapter);
> >
> >   	return nb_rx;
> >
> 
> After this change, is there any point in having the event_enqueue_buffer
> being a part of the rx_adapter struct? It could be stack allocated. In the
> process, you could eliminate the rte_event copying that goes on and the
> logic around that. Just make mbufs ETH_EVENT_BUFFER_SIZE in size, and
> retry until the NIC queue is empty or you accumulated
> ETH_EVENT_BUFFER_SIZE events. Then you ship it off to the event device.

You are right, I will post a separate (from the bug fix) patch for this.

Thanks,
Nikhil