[dpdk-dev] overcommitting CPUs

[Zhou, Danny]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Stephen Hemminger
> Sent: Wednesday, August 27, 2014 12:39 AM
> To: Michael Marchetti
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] overcommitting CPUs
> 
> On Tue, 26 Aug 2014 16:27:14 +0000
> "Michael  Marchetti" <mmarchetti at sandvine.com> wrote:
> 
> > Hi, has there been any consideration to introduce a non-spinning network driver (interrupt based), for the purpose of overcommitting
> CPUs in a virtualized environment?  This would obviously have reduced high-end performance but would allow for increased guest
> density (sharing of physical CPUs) on a host.
> >
> > I am interested in adding support for this kind of operation, is there any interest in the community?
> >
> > Thanks,
> >
> > Mike.
> 
> Better to implement a NAPI like algorithm that adapts from poll to interrupt.

Agreed, but DPDK is currently pure poll-mode based, so unlike the NAPI' simple algorithm, the new heuristic algorithm should not switch from poll-mode to interrupt-mode immediately once there is no packet in the recent poll. Otherwise, mode switching will be too frequent which brings serious negative performance impact to DPDK.