[dpdk-dev] FW: Issues on FDIR and multi-processes

[Mauro Annarumma <mauroannarumma@hotmail.it>]

Hi Bruce,
thanks for the reply; I'm trying to do what you suggest, in particular I set the value of the lcore_id variable with this instruction:

RTE_PER_LCORE(_lcore_id) = temp_lcore_id;

where temp_lcore_id is a unique id strictly less then RTE_MAX_LCORE; the instruction is placed just after the "rte_eal_init" call in my main function.

   I still have the same problem whit the secondary processes. Do you think there could be other issues with the secondary-processes on the some core? Did I do something wrong   in the _lcore_id setting?
Regards.

Mauro 


> From: bruce.richardson@intel.com
> To: mauroannarumma@hotmail.it; dev@dpdk.org
> Subject: RE: [dpdk-dev] Issues on FDIR and multi-processes
> Date: Wed, 2 Apr 2014 15:33:09 +0000
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Mauro Annarumma
> > Sent: Wednesday, April 02, 2014 4:02 PM
> > To: dev@dpdk.org
> > Subject: [dpdk-dev] Issues on FDIR and multi-processes
> > 
> > Hi everyone,
> > we are working with Flow DIRector on a multiprocess application. This application consists of N secondary processes, 
> > each one receiving packets directly from its own queue on the NIC. It works fine when each secondary process runs on
> > a different CPU core; instead, if we try to run two secondary processes on the same CPU core, these processes aren't 
> > able to read from their respectively queue.
> 
> Running two co-operating Intel DPDK processes on the same lcore is not a supported configuration of Intel DPDK multiprocess. [Please see section 20.3 of the Intel DPDK Programmer's Guide document, which lists out some limitations of multi-process support]. Basically, each process in a multiprocess configuration is equivalent to a thread in a normal application deployment, so just as having two threads on the same core causes problems with mempools and other objects which use an "lcore_id" value unique in each thread to work correctly, so running two processes on the same lcore can cause exactly the same issues. 
> If you really do want to use this model and have multiple threads on the same lcore, at minimum you need to ensure that each thread/process has a unique lcore_id value <= RTE_MAX_LCORE.
> 
> /Bruce