On Wednesday, April 12, 2023 9:31 AM, Song Yoong Siang <yoong.siang.song@xxxxxxxxx> wrote: >On Tuesday, April 11, 2023 12:25 AM, Stanislav Fomichev <sdf@xxxxxxxxxx> >wrote: >>On 04/10, Song Yoong Siang wrote: >>> Add receive hardware timestamp metadata support via kfunc to XDP >>> receive packets. >>> >>> Signed-off-by: Song Yoong Siang <yoong.siang.song@xxxxxxxxx> >>> --- >>> drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 + >>> .../net/ethernet/stmicro/stmmac/stmmac_main.c | 24 >>> +++++++++++++++++-- >>> 2 files changed, 23 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h >>> b/drivers/net/ethernet/stmicro/stmmac/stmmac.h >>> index ac8ccf851708..760445275da8 100644 >>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h >>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h >>> @@ -94,6 +94,7 @@ struct stmmac_rx_buffer { >>> >>> struct stmmac_xdp_buff { >>> struct xdp_buff xdp; >>> + ktime_t rx_hwts; >>> }; >>> >>> struct stmmac_rx_queue { >>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> index f7bbdf04d20c..ca183fbfde85 100644 >>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c >>> @@ -5307,6 +5307,8 @@ static int stmmac_rx(struct stmmac_priv *priv, >>> int >>limit, u32 queue) >>> } >>> } >>> >> >>[..] >> >>> + stmmac_get_rx_hwtstamp(priv, p, np, &ctx.rx_hwts); >> >>Do we want to pay this cost for every packet? >> >>The preferred alternative is to store enough state in the >>stmmac_xdp_buff so we can get to this data from stmmac_xdp_rx_timestamp. >> >>I haven't read this code, but tentatively: >>- move priv, p, np into stmmac_xdp_buff, assign them here instead of >> calling stmmac_get_rx_hwtstamp >>- call stmmac_get_rx_hwtstamp from stmmac_xdp_rx_timestamp with the >> stored priv, p, np >> >>That would ensure that we won't waste the cycles pulling out the rx >>timestamp for every packet if the higher levels / users don't care. >> >>Would something like this work? > >Hi Stanislav Fomichev, > >Thanks for your comments. > >Original stmmac_rx() function is already calling stmmac_get_rx_hwtstamp() for >every packet. This patch move the calling of stmmac_get_rx_hwtstamp() earlier >so that rx timestamp is available before running bpf_prog_run_xdp(). So, i think >no additional cost introduced here. Any other thoughts? > >Furthermore, stmmac_get_rx_hwtstamp() will check whether hw timestamp is >enabled in driver and available in the descriptor before getting the hw timestamp. > Hi Stanislav Fomichev, I think twice. It might add some latency for certain verdict if the hw timestamp is enabled but the user app dint need it. I will take your suggestion and try to pull the timestamp per need basic. Will submit v3 soon. Thanks & Regards Siang >> >>> + >>> if (!skb) { >>> unsigned int pre_len, sync_len; >>> >>> @@ -5315,7 +5317,7 @@ static int stmmac_rx(struct stmmac_priv *priv, >>> int limit, u32 queue) >>> >>> xdp_init_buff(&ctx.xdp, buf_sz, &rx_q->xdp_rxq); >>> xdp_prepare_buff(&ctx.xdp, page_address(buf->page), >>> - buf->page_offset, buf1_len, false); >>> + buf->page_offset, buf1_len, true); >>> >>> pre_len = ctx.xdp.data_end - ctx.xdp.data_hard_start - >>> buf->page_offset; >>> @@ -5411,7 +5413,7 @@ static int stmmac_rx(struct stmmac_priv *priv, >>> int limit, u32 queue) >>> >>> shhwtstamp = skb_hwtstamps(skb); >>> memset(shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps)); >>> - stmmac_get_rx_hwtstamp(priv, p, np, &shhwtstamp->hwtstamp); > >Original stmmac_get_rx_hwtstamp() function is called here. > >Thanks & Regards >Siang > >>> + shhwtstamp->hwtstamp = ctx.rx_hwts; >>> >>> stmmac_rx_vlan(priv->dev, skb); >>> skb->protocol = eth_type_trans(skb, priv->dev); @@ -7071,6 >>+7073,22 >>> @@ void stmmac_fpe_handshake(struct stmmac_priv *priv, bool enable) >>> } >>> } >>> >>> +static int stmmac_xdp_rx_timestamp(const struct xdp_md *_ctx, u64 >>> +*timestamp) { >>> + const struct stmmac_xdp_buff *ctx = (void *)_ctx; >>> + >>> + if (ctx->rx_hwts) { >>> + *timestamp = ctx->rx_hwts; >>> + return 0; >>> + } >>> + >>> + return -ENODATA; >>> +} >>> + >>> +const struct xdp_metadata_ops stmmac_xdp_metadata_ops = { >>> + .xmo_rx_timestamp = stmmac_xdp_rx_timestamp, >>> +}; >>> + >>> /** >>> * stmmac_dvr_probe >>> * @device: device pointer >>> @@ -7178,6 +7196,8 @@ int stmmac_dvr_probe(struct device *device, >>> >>> ndev->netdev_ops = &stmmac_netdev_ops; >>> >>> + ndev->xdp_metadata_ops = &stmmac_xdp_metadata_ops; >>> + >>> ndev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | >>NETIF_F_IPV6_CSUM | >>> NETIF_F_RXCSUM; >>> ndev->xdp_features = NETDEV_XDP_ACT_BASIC | >>NETDEV_XDP_ACT_REDIRECT >>> | >>> -- >>> 2.34.1 >>>