[dpdk-dev] Cannot mmap device resource in DPDK 1.7.0 multi-process/multi-thread

[Richardson, Bruce]

> -----Original Message-----
> From: Mario Gianni [mailto:m.gianni at engineer.com]
> Sent: Friday, October 24, 2014 4:03 PM
> To: Richardson, Bruce
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] Cannot mmap device resource in DPDK 1.7.0 multi-
> process/multi-thread
> 
> So you are telling me that in order to implement multi-process I should better
> use the l2fwd_fork example instead of client_server_mp.
> In fact if I use the client_server_mp with a lot of mp_client threads it gives me
> the error.
> If instead I use the l2fwd_fork example it doesn't give me the error.
> 
> One more question at this point:
> Assume that I use l2fwd_fork, when I launch the secondary process, how do I
> assign the lcore coremask associated with that process?
> 

With the l2fwd_fork example, the forked processes are not secondary proceses in the sense of the other DPDK multiprocess models - with each one having its own core mask and set of threads. Instead, each forked process is a single thread based off the core-mask provided at process startup. It's a different way of doing things, but one which provides separate processes, while guaranteeing that all processes can share the same hugepage memory at the same address without relying on having the kernel map things at specific points in the address space.

/Bruce