[dpdk-dev] [PATCH v1 1/6] build: increase default of max lcores to 512

[David Marchand]

On Tue, Sep 14, 2021 at 1:07 PM David Hunt <david.hunt at intel.com> wrote:
> >> “ERROR: logical core 212 is above the maximum lcore number permitted.
> >> Please use the --lcores option to map lcores onto physical cores, e.g.
> >> --lcores="(0-3)@(212-215).”
> > If you could directly provide the right --lcores syntax based on what
> > user provided with -c or -l, it would be even better.
> > This should be not that difficult.
>
>
> Agreed. I now have something working that when given "-l 12-16,130,132",
> will output the following:
>
> EAL: One of the 7 cores provided exceeds RTE_MAX_LCORE (128)
> EAL: Please use --lcores instead, e.g. --lcores "(0-6)@(12-16,130,132)"

That's not equivalent.

(0-6)@(12-16,130,132) means 7 lcores with each lcore running on the
same group of physical cores.
-l 12-16,130,132 means 7 lcores running on dedicated physical cores.
I would expect 0 at 12,1 at 13,2 at 14,3 at 15,4 at 16,5 at 130,6 at 132


You can see with debug logs:

$ echo quit | ./build/app/dpdk-testpmd --log-level=*:debug --no-huge
-m 512 --lcores '(0-2)@(0-2)' -- --total-num-mbufs 2048 |& grep
lcore.*is.ready
EAL: Main lcore 0 is ready (tid=7feb9550bc00;cpuset=[0,1,2])
EAL: lcore 1 is ready (tid=7feb909ce700;cpuset=[0,1,2])
EAL: lcore 2 is ready (tid=7feb901cd700;cpuset=[0,1,2])

vs

$ echo quit | ./build/app/dpdk-testpmd --log-level=*:debug --no-huge
-m 512 --lcores 0 at 0,1 at 1,2 at 2 -- --total-num-mbufs 2048 |& grep
lcore.*is.ready
EAL: Main lcore 0 is ready (tid=7fba1cd1ac00;cpuset=[0])
EAL: lcore 2 is ready (tid=7fba179dc700;cpuset=[2])
EAL: lcore 1 is ready (tid=7fba181dd700;cpuset=[1])


-- 
David Marchand