On Wed, Oct 28, 2020 at 9:00 PM Liang, Ma <liang.j...@intel.com> wrote:
>
> On 28 Oct 20:44, Jerin Jacob wrote:
> > On Wed, Oct 28, 2020 at 8:27 PM Ananyev, Konstantin
> > <konstantin.anan...@intel.com> wrote:
> > >
> > >
> > >
> > > > 28/10/2020 14:49, Jerin Jacob:
> > > > > On Wed, Oct 28, 2020 at 7:05 PM Liang, Ma <liang.j...@intel.com> 
> > > > > wrote:
> > > > > >
> > > > > > Hi Thomas,
> > > > > >   I think I addressed all of the questions in relation to V9. I 
> > > > > > don't think I can solve the issue of a generic API on my own. From 
> > > > > > the
> > > > Community Call last week Jerin also said that a generic was 
> > > > investigated but that a single solution wasn't feasible.
> > > > >
> > > > > I think, From the architecture point of view, the specific
> > > > > functionally of UMONITOR may not be abstracted.
> > > > > But from the ethdev callback point of view, Can it be abstracted in
> > > > > such a way that packet notification available through
> > > > > checking interrupt status register or ring descriptor location, etc by
> > > > > the driver. Use that callback as a notification mechanism rather
> > > > > than defining a memory-based scheme that UMONITOR expects? or similar
> > > > > thoughts on abstraction.
> > >
> > > I think there is probably some sort of misunderstanding.
> > > This API is not about providing acync notification when next packet 
> > > arrives.
> > > This is about to putting core to sleep till some event (or timeout) 
> > > happens.
> > > From my perspective the closest analogy: cond_timedwait().
> > > So we need PMD to tell us what will be the address of the condition 
> > > variable
> > > we should sleep on.
> > >
> > > > I agree with Jerin.
> > > > The ethdev API is the blocking problem.
> > > > First problem: it is not well explained in doxygen.
> > > > Second problem: it is probably not generic enough (if we understand it 
> > > > well)
> > >
> > > It is an address to sleep(/wakeup) on, plus expected value.
> > > Honestly, I can't think-up of anything even more generic then that.
> > > If you guys have something particular in mind - please share.
> >
> > Current PMD callback:
> > typedef int (*eth_get_wake_addr_t)(void *rxq, volatile void
> > **tail_desc_addr, + uint64_t *expected, uint64_t *mask, uint8_t
> > *data_sz);
> >
> > Can we make it as
> > typedef void (*core_sleep_t)(void *rxq)
> How about void (*eth_core_sleep_helper_t)(void *rxq, enum scheme, void 
> *paramter)
> by this way, PMD can cast the parameter accorind to the scheme.
> e.g.  if scheme  MEM_MONITOR then cast to umwait way.
> however, this will introduce another problem.
> we need add PMD query callback to figure out if PMD support this scheme.

I thought scheme/policy something that "application cares" like below
not arch specifics
1) wakeup up on first packet,
2) wake me up on first packet or timeout 100 us etc

Yes. We can have query on type of the policies supported.


> >
> > if we do such abstraction and "move the polling on memory by HW/CPU"
> > to the driver using a helper function then
> > I can think of abstracting in some way in all PMDs.
> >
> > Note: core_sleep_t can take some more arguments such as enumerated
> > policy if something more needs to be pushed to the driver.
> >
> > Thoughts?
> >
> > >
> > > >
> > > > > > This API is experimental and other vendor support can be added as 
> > > > > > needed. If there are any other open issue let me know?
> > > >
> > > > Being experimental is not an excuse to throw something
> > > > which is not satisfying.
> > > >
> > > >
> > >

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