Re: [dpdk-dev] [PATCH] eventdev: Add rte_errno return values to the enqueue and dequeue functions

[Bruce Richardson <bruce.richardson@intel.com>]

On Mon, Feb 13, 2017 at 05:18:11PM +0530, Jerin Jacob wrote:
> On Mon, Feb 13, 2017 at 10:38:55AM +0000, Bruce Richardson wrote:
> > On Fri, Feb 10, 2017 at 03:02:21PM -0600, Gage Eads wrote:
> > > This change allows user software to differentiate between an invalid argument
> > > (such as an invalid queue_id or sched_type in an enqueued event) and
> > > backpressure from the event device.
> > > 
> > > The port and device ID checks are placed in RTE_LIBRTE_EVENTDEV_DEBUG header
> > > guards to avoid the performance hit in non-debug execution.
> > > 
> > > Signed-off-by: Gage Eads <gage.eads@intel.com>
> > > ---
> > 
> > Do we have some idea of the performance hit from these? It may be too
> > soon to know, given we don't have many drivers to test with, but if
> > there is no perf hit seen with the SW driver, I think we should look to
> > just always do this, rather than having it compile-time off. If it does
> 
> IMO, It is better put to under compile-time like ethdev. It is
> difficult predict the performance regression on wide range of cores that DPDK
> runs now. I think we need to add following additional checks based on
> Gage header file change
> 
> 1) Per event queue ID is valid or not?
> 2) Per event's sched type doesn't match the capabilities of the destination queue.
> 

Ok, if we are expanding the number of checks then I definitely think it
needs to be compile-time selected.

/Bruce
> 
> > prove to be a performance problem we can look to #ifdef it out later.
> > 
> > /Bruce