[dpdk-users] Coremask

Stephen Hemminger stephen at networkplumber.org
Wed Apr 13 20:10:13 CEST 2016

On Wed, 13 Apr 2016 09:42:29 -0700
Cliff Burdick <shaklee3 at gmail.com> wrote:

> I don't see the answer to this in the documentation, so I'll try here. Why
> function does the coremask that's required in rte_eal_init() actually do
> other than tell the API what cores you're using? In other words, can't I
> just set the core mask to all of the cores in my system, and selectively
> use the ones I want? Is there a downside to that? What if the particular
> thread running on an lcore isn't doing any DPDK functions?

The coremask is used to determine which CPU's are setup and a per-cpu
thread is started by the launch operation.

You can tell EAL about as many CPU's as you want, either all or even
just one. If you use all CPU's, then in the launch it is possible to
have the thread function of unneeded CPU's return and go back to the launch idle loop.

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