[dpdk-dev] [PATCH 1/4] eventdev: introduce event driven programming model

[Bruce Richardson]

On Thu, Nov 24, 2016 at 07:29:13AM +0530, Jerin Jacob wrote:
> On Wed, Nov 23, 2016 at 07:39:09PM +0100, Thomas Monjalon wrote:

Just some comments on mine triggered by Thomas comments?

<snip>
> > + */
> > > +static inline int
> > > +rte_event_enqueue(uint8_t dev_id, uint8_t port_id, struct rte_event *ev)
> > 
> > Is it really needed to have non-burst variant of enqueue/dequeue?
> 
> Yes. certain HW can work only with non burst variants.

In those cases is it not acceptable just to have the dequeue_burst
function return 1 all the time? It would allow apps to be more portable
between burst and non-burst varients would it not.

> > 
> > > +/**
> > > + * Converts nanoseconds to *wait* value for rte_event_dequeue()
> > > + *
> > > + * If the device is configured with RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT flag then
> > > + * application can use this function to convert wait value in nanoseconds to
> > > + * implementations specific wait value supplied in rte_event_dequeue()
> > 
> > Why is it implementation-specific?
> > Why this conversion is not internal in the driver?
> 
> This is for performance optimization, otherwise in drivers
> need to convert ns to ticks in "fast path"
> 
> > 
Is that really likely to be a performance bottleneck. I would expect
modern cores to fly through basic arithmetic in a negligable amount of
cycles?

/Bruce