On Wed, 30 Apr 2025 15:48:36 +0200
Oleksandr Kolomeiets <okl-...@napatech.com> wrote:
> From: Danylo Vodopianov <dvo-...@napatech.com>
>
> Sometimes during high flow learn performance two threads
> could cause deadlock using queue and mutex.
>
> learn_ignored variable sets when flow learn and gets
> when flow removes. Hence, learn_ignore should not be protected
> as far as two thread could not access to the same flow
> at the same time.
>
> Signed-off-by: Danylo Vodopianov <dvo-...@napatech.com>
If you are going to do this, then you need to use rte_atomic_store/fetch.
If two threads read/write same variable outside of lock, need the CPU
to use special instructions on weakly ordered platforms like ARM.
> --- a/drivers/net/ntnic/include/flow_api_engine.h
> +++ b/drivers/net/ntnic/include/flow_api_engine.h
> @@ -297,7 +297,7 @@ struct flow_handle {
> enum flow_handle_type type;
> uint32_t flm_id;
> uint16_t caller_id;
> - uint16_t learn_ignored;
> + RTE_ATOMIC(uint16_t)learn_ignored;
The preferred spacing would be:
RTE_ATOMIC(uint16_t) learn_ignored;
