Re: [dpdk-dev] [PATCH v3 2/2] eal: restrict ctrl threads to startup cpu affinity

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 19-Feb-19 8:41 PM, David Marchand wrote:
> Spawning the ctrl threads on anything that is not part of the eal
> coremask is not that polite to the rest of the system, especially
> when you took good care to pin your processes on cpu resources with
> tools like taskset (linux) / cpuset (freebsd).
> 
> Rather than introduce yet another eal options to control on which cpu
> those ctrl threads are created, let's take the startup cpu affinity
> as a reference and remove the eal coremask from it.
> If no cpu is left, then we default to the master core.
> 
> The cpuset is computed once at init before the original cpu affinity
> is lost.
> 
> Introduced a RTE_CPU_AND macro to abstract the differences between linux
> and freebsd respective macros.
> 
> Examples in a 4 cores FreeBSD vm:
> 
> $ ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
>   -- -i --total-num-mbufs=2048
> 
> $ procstat -S 1057
>    PID    TID COMM                TDNAME              CPU CSID CPU MASK
>   1057 100131 testpmd             -                     2    1 2
>   1057 100140 testpmd             eal-intr-thread       1    1 0-1
>   1057 100141 testpmd             rte_mp_handle         1    1 0-1
>   1057 100142 testpmd             lcore-slave-3         3    1 3
> 
> $ cpuset -l 1,2,3 ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
>   -- -i --total-num-mbufs=2048
> 
> $ procstat -S 1061
>    PID    TID COMM                TDNAME              CPU CSID CPU MASK
>   1061 100131 testpmd             -                     2    2 2
>   1061 100144 testpmd             eal-intr-thread       1    2 1
>   1061 100145 testpmd             rte_mp_handle         1    2 1
>   1061 100147 testpmd             lcore-slave-3         3    2 3
> 
> $ cpuset -l 2,3 ./build/app/testpmd -l 2,3 --no-huge --no-pci -m 512 \
>   -- -i --total-num-mbufs=2048
> 
> $ procstat -S 1065
>    PID    TID COMM                TDNAME              CPU CSID CPU MASK
>   1065 100131 testpmd             -                     2    2 2
>   1065 100148 testpmd             eal-intr-thread       2    2 2
>   1065 100149 testpmd             rte_mp_handle         2    2 2
>   1065 100150 testpmd             lcore-slave-3         3    2 3
> 
> Fixes: d651ee4919cd ("eal: set affinity for control threads")
> Cc: stable@dpdk.org
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---

Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly