On 12/21/18, 10:59 AM, "Mattias Rönnblom" <mattias.ronnb...@ericsson.com>
wrote:
On 2018-12-21 19:34, Venky Venkatesh wrote:
>
>
> On 12/21/18, 10:24 AM, "Mattias Rönnblom" <mattias.ronnb...@ericsson.com>
wrote:
>
> On 2018-12-21 06:13, Venky Venkatesh wrote:
> > Hi,
> > We are considering using a multi-process mode of the DPDK with the
event generators and consumers being spread across multiple processes (on
different cores). We are also considering using the DSW eventdev. Is the DSW
designed for such a use case? If so, are there some restrictions and something
specific that need to be done to make it work correctly?
> >
>
> The purpose of an event device is to do dynamic load balancing across
> multiple cores. Using the DPDK multiple-process support, with its
> requirement of having unique, non-overlapping, core masks works
against
> or even defeats this purpose.
>
> [VV]: I don’t understand your last sentence. Suppose I am having multiple
packet processing processes (each with a single thread and polling a disjoint
set of queues) and each linked to DSW. Each process would invoke the enqueue
which will be handled by the DSW linked to that process. Will the DSWs across
these processes "collaborate" to get load balancing across the processes?
>
If the processes are to collaborate, and process packets in the same
pipeline, they will need to share an event device (for example, a DSW
instance).
However, if you put each of your pipeline stages into a process with a
single worker thread, you will not leave any room for an event device to
load balance, since every eventdev queue will have only a single
consumer linked to it.
[VV]: Sorry for the ambiguous terminology used by me -- queue (above) referred
to port queues and not eventdev queues. Additionally, consider a very simple
pipeline -- just 1 stage followed by transmit. Thus each process is pulling
packets out of the port queue, enqueue into local DSW, dequeue from local DSW
and running this 1 stage pipeline and transmitting. The role of eventdev in
this world is to load balance across the processes -- that is what I meant by
DSWs collaborate (since they need to exchange load information and do migration
handshake). Hope that clarifies. Pls let me know if this will work.
