Re: [dpdk-dev] Having troubles binding an SR-IOV VF to uio_pci_generic on Amazon instance

[Gleb Natapov <gleb@scylladb.com>]

On Wed, Sep 30, 2015 at 11:36:58PM +0300, Michael S. Tsirkin wrote:
> On Wed, Sep 30, 2015 at 11:00:49PM +0300, Gleb Natapov wrote:
> > > You are increasing interrupt latency by a huge factor by channeling
> > > interrupts through a scheduler.  Let user install an
> > > interrupt handler function, and be done with it.
> > > 
> > Interrupt latency is not always hugely important. If you enter interrupt
> > mode only when idle hundred more us on a first packet will not kill you.
> 
> It certainly affects worst-case latency.  And if you lower interupt
> latency, you can go idle faster, so it affects power too.
> 
We are polling 100% now. Going idle faster is the least of our concern.

> > If
> > interrupt latency is important then uio may be not the right solution,
> > but then neither is vfio.
> 
> That's what I'm saying, if you don't need memory isolation you can do
> better than just slightly tweak existing drivers.
> 
No, you are forcing everyone to code in kernel no matter if it make
sense or not. You decide for everyone what is good for them. Believe me
people here know about trade-offs and made appropriate considerations.

--
			Gleb.