On Fri, Mar 6, 2020 at 10:35 AM Gavin Hu <gavin...@arm.com> wrote:
>
> Tx mbuf free is a hotspot for i40e on aarch64, as there are no
> inter-loop dependencies, it is safe to enable auto-vectorization
> to speed up.
>
> This patch showed 2~3% performance lift on ThunderX2 and no degradation
> on Arm N1SDP. The test case is single core RFC2544 zero-loss test.
>
> Signed-off-by: Gavin Hu <gavin...@arm.com>
> Reviewed-by: Steve Capper <steve.cap...@arm.com>
> ---
> drivers/net/i40e/i40e_rxtx_vec_common.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/net/i40e/i40e_rxtx_vec_common.h
> b/drivers/net/i40e/i40e_rxtx_vec_common.h
> index 0e6ffa007..fc0fa45d4 100644
> --- a/drivers/net/i40e/i40e_rxtx_vec_common.h
> +++ b/drivers/net/i40e/i40e_rxtx_vec_common.h
> @@ -98,6 +98,11 @@ i40e_tx_free_bufs(struct i40e_tx_queue *txq)
> if (likely(m != NULL)) {
> free[0] = m;
> nb_free = 1;
> +#if defined(__clang__)
> +#pragma clang loop vectorize(assume_safety)
> +#elif defined(__GNUC__)
> +#pragma GCC ivdep
> +#endif
IMO, It is better to abstract the compiler features (above compiler
feature and __restrict__) as macros in
rte_common.h or so. It will help to support other compilers(ICC or
Windows) and enable them to have "changes" in one place.
> for (i = 1; i < n; i++) {
> m = rte_pktmbuf_prefree_seg(txep[i].mbuf);
> if (likely(m != NULL)) {
> --
> 2.17.1
>
