From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1956BC00A89 for ; Thu, 5 Nov 2020 07:19:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EB5120936 for ; Thu, 5 Nov 2020 07:19:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="L3f1l1H1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727245AbgKEHTX (ORCPT ); Thu, 5 Nov 2020 02:19:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727114AbgKEHTW (ORCPT ); Thu, 5 Nov 2020 02:19:22 -0500 Received: from mail-pg1-x543.google.com (mail-pg1-x543.google.com [IPv6:2607:f8b0:4864:20::543]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A88D2C0613CF; Wed, 4 Nov 2020 23:19:22 -0800 (PST) Received: by mail-pg1-x543.google.com with SMTP id f38so754711pgm.2; Wed, 04 Nov 2020 23:19:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=1TLgog7JBgHorKNM3wu5oUyqgLdnRdAs11pbRUNSTBw=; b=L3f1l1H1g9M6vyiNZZR4pDhuTZwnL5Q+PH/q7i9xri9FLJIIfMK4Sp6Ly3VPONYFcc bR8v0k17u3+8Fpqubf79f7dNaAXTg/0JBymxFMKkbPcCi2/pAgVaWYELG8iyW9FNBN1d Go1wwOVlaNnZwkC/kvp1FlE9V91LVhgxNwz0PyELvsrVYs+cc1A5TJf8KrmFVf3Q0Dxp HlPqCQsGcyUSe796N1DS/i1+ptTF/53LPJtjc7tYg5rrNf79EblAG8gjTdB2nSRL9vcM KDzewdwg6mbCQCSaEEQb5CvUgrvbP4vCr0nqc69ZUfprvdcUAWra2U41thsusWuqdevy oUjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=1TLgog7JBgHorKNM3wu5oUyqgLdnRdAs11pbRUNSTBw=; b=h3w4gHNXJYvOX/gaDxcPcLK5NV4GSS32xbOFK0c0UQ82o+6PBGuTE0/igxkbWEJA3T YwMkkl+8sqaeSJipt7mPGMJuHALX/jogSfTp5kKRR/O1pyl/HP9HHx2i6dwmmQEYNskR JOKCIyCr76D7MviHcugzy6Gy2tieXgKei6RgJoZ8EI8wJPx0VQljtK+tEVMdzHNHXG/F Kjd5+UkXe/pFMgE1/tgxXHxc0EV+dalGzWg3aqIaVEeREat3iBCwJqKau/RqELGNvN46 qK+qND70O6W1kHu6+U28jCNeUEhEVCrcyAMBVj0btUTfK5Xa/M+7kFs4AaexoLlgHVnj RRdA== X-Gm-Message-State: AOAM532xiYDXbUs37qDC21wT+1fnwxH8Hvy9XoQLCxS6z4dyEBl58x1t OLs+TGm2KBgtvM+E+iNp1wU33Gx6fS6IuqFQXoY= X-Google-Smtp-Source: ABdhPJz3LEKOTubGfhWi7zbZ4YpD4hVn0AU2fTZyOc0OeVA0nJurOEQnwP6zmKj/hKmVz1OltWRPsV9CA71iIk9RYws= X-Received: by 2002:aa7:8428:0:b029:18b:b43:6cc with SMTP id q8-20020aa784280000b029018b0b4306ccmr1161992pfn.73.1604560762121; Wed, 04 Nov 2020 23:19:22 -0800 (PST) MIME-Version: 1.0 References: <1604498942-24274-1-git-send-email-magnus.karlsson@gmail.com> <1604498942-24274-7-git-send-email-magnus.karlsson@gmail.com> <20201104230122.GA40117@ranger.igk.intel.com> In-Reply-To: <20201104230122.GA40117@ranger.igk.intel.com> From: Magnus Karlsson Date: Thu, 5 Nov 2020 08:19:11 +0100 Message-ID: Subject: Re: [PATCH bpf-next 6/6] i40e: use batched xsk Tx interfaces to increase performance To: Maciej Fijalkowski Cc: "Karlsson, Magnus" , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Alexei Starovoitov , Daniel Borkmann , Network Development , Jonathan Lemon , bpf , jeffrey.t.kirsher@intel.com, anthony.l.nguyen@intel.com, Maciej Fijalkowski , intel-wired-lan Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Nov 5, 2020 at 12:12 AM Maciej Fijalkowski wrote: > > On Wed, Nov 04, 2020 at 03:09:02PM +0100, Magnus Karlsson wrote: > > From: Magnus Karlsson > > > > Use the new batched xsk interfaces for the Tx path in the i40e driver > > to improve performance. On my machine, this yields a throughput > > increase of 4% for the l2fwd sample app in xdpsock. If we instead just > > look at the Tx part, this patch set increases throughput with above > > 20% for Tx. > > > > Note that I had to explicitly loop unroll the inner loop to get to > > this performance level, by using a pragma. It is honored by both clang > > and gcc and should be ignored by versions that do not support > > it. Using the -funroll-loops compiler command line switch on the > > source file resulted in a loop unrolling on a higher level that > > lead to a performance decrease instead of an increase. > > > > Signed-off-by: Magnus Karlsson > > --- > > drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 2 +- > > drivers/net/ethernet/intel/i40e/i40e_main.c | 4 +- > > drivers/net/ethernet/intel/i40e/i40e_txrx.c | 14 ++- > > drivers/net/ethernet/intel/i40e/i40e_txrx.h | 3 +- > > drivers/net/ethernet/intel/i40e/i40e_xsk.c | 127 ++++++++++++++++++------- > > 5 files changed, 110 insertions(+), 40 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c > > index 26ba1f3..dc34867 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c > > @@ -2025,7 +2025,7 @@ static int i40e_set_ringparam(struct net_device *netdev, > > */ > > tx_rings[i].desc = NULL; > > tx_rings[i].rx_bi = NULL; > > - err = i40e_setup_tx_descriptors(&tx_rings[i]); > > + err = i40e_setup_tx_descriptors(&tx_rings[i], false); > > if (err) { > > while (i) { > > i--; > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c > > index 4f8a2154..c93774a 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_main.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c > > @@ -3030,13 +3030,13 @@ static int i40e_vsi_setup_tx_resources(struct i40e_vsi *vsi) > > int i, err = 0; > > > > for (i = 0; i < vsi->num_queue_pairs && !err; i++) > > - err = i40e_setup_tx_descriptors(vsi->tx_rings[i]); > > + err = i40e_setup_tx_descriptors(vsi->tx_rings[i], false); > > > > if (!i40e_enabled_xdp_vsi(vsi)) > > return err; > > > > for (i = 0; i < vsi->num_queue_pairs && !err; i++) > > - err = i40e_setup_tx_descriptors(vsi->xdp_rings[i]); > > + err = i40e_setup_tx_descriptors(vsi->xdp_rings[i], true); > > One last suggestion: I think that you could just call ring_is_xdp(tx_ring) > within i40e_setup_tx_descriptors() and based on that allocate the > xsk_descs array, instead of parametrizing the function. At the time of > setting up tx descs the I40E_TXR_FLAGS_XDP flag is already set. > > I think this would be a cleaner way of doing it. Yes, good suggestion. Will do that. > > > > return err; > > } > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > index d43ce13..3e13e0e 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > @@ -676,6 +676,8 @@ void i40e_free_tx_resources(struct i40e_ring *tx_ring) > > i40e_clean_tx_ring(tx_ring); > > kfree(tx_ring->tx_bi); > > tx_ring->tx_bi = NULL; > > + kfree(tx_ring->xsk_descs); > > + tx_ring->xsk_descs = NULL; > > > > if (tx_ring->desc) { > > dma_free_coherent(tx_ring->dev, tx_ring->size, > > @@ -1259,10 +1261,11 @@ void i40e_clean_programming_status(struct i40e_ring *rx_ring, u64 qword0_raw, > > /** > > * i40e_setup_tx_descriptors - Allocate the Tx descriptors > > * @tx_ring: the tx ring to set up > > + * @xdp_ring: true if this is an XDP Tx ring > > * > > * Return 0 on success, negative on error > > **/ > > -int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring) > > +int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring, bool xdp_ring) > > { > > struct device *dev = tx_ring->dev; > > int bi_size; > > @@ -1277,6 +1280,13 @@ int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring) > > if (!tx_ring->tx_bi) > > goto err; > > > > + if (xdp_ring) { > > + tx_ring->xsk_descs = kcalloc(I40E_MAX_NUM_DESCRIPTORS, sizeof(*tx_ring->xsk_descs), > > + GFP_KERNEL); > > + if (!tx_ring->xsk_descs) > > + goto err; > > + } > > + > > u64_stats_init(&tx_ring->syncp); > > > > /* round up to nearest 4K */ > > @@ -1300,6 +1310,8 @@ int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring) > > return 0; > > > > err: > > + kfree(tx_ring->xsk_descs); > > + tx_ring->xsk_descs = NULL; > > kfree(tx_ring->tx_bi); > > tx_ring->tx_bi = NULL; > > return -ENOMEM; > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h > > index 2feed92..628d5d7 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h > > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h > > @@ -389,6 +389,7 @@ struct i40e_ring { > > struct i40e_channel *ch; > > struct xdp_rxq_info xdp_rxq; > > struct xsk_buff_pool *xsk_pool; > > + struct xdp_desc *xsk_descs; /* For storing descriptors in the AF_XDP ZC path */ > > } ____cacheline_internodealigned_in_smp; > > > > static inline bool ring_uses_build_skb(struct i40e_ring *ring) > > @@ -451,7 +452,7 @@ bool i40e_alloc_rx_buffers(struct i40e_ring *rxr, u16 cleaned_count); > > netdev_tx_t i40e_lan_xmit_frame(struct sk_buff *skb, struct net_device *netdev); > > void i40e_clean_tx_ring(struct i40e_ring *tx_ring); > > void i40e_clean_rx_ring(struct i40e_ring *rx_ring); > > -int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring); > > +int i40e_setup_tx_descriptors(struct i40e_ring *tx_ring, bool xdp_ring); > > int i40e_setup_rx_descriptors(struct i40e_ring *rx_ring); > > void i40e_free_tx_resources(struct i40e_ring *tx_ring); > > void i40e_free_rx_resources(struct i40e_ring *rx_ring); > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > index eabe1a3..515d856 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > @@ -383,6 +383,78 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget) > > return failure ? budget : (int)total_rx_packets; > > } > > > > +static void i40e_xmit_pkt(struct i40e_ring *xdp_ring, struct xdp_desc *desc, > > + unsigned int *total_bytes) > > +{ > > + struct i40e_tx_desc *tx_desc; > > + dma_addr_t dma; > > + > > + dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, desc->addr); > > + xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma, desc->len); > > + > > + tx_desc = I40E_TX_DESC(xdp_ring, xdp_ring->next_to_use++); > > + tx_desc->buffer_addr = cpu_to_le64(dma); > > + tx_desc->cmd_type_offset_bsz = build_ctob(I40E_TX_DESC_CMD_ICRC | I40E_TX_DESC_CMD_EOP, > > + 0, desc->len, 0); > > + > > + *total_bytes += desc->len; > > +} > > + > > +/* This value should match the pragma below. Why 4? It is strictly > > + * empirical. It seems to be a good compromise between the advantage > > + * of having simultaneous outstanding reads to the DMA array that can > > + * hide each others latency and the disadvantage of having a larger > > + * code path. > > + */ > > +#define PKTS_PER_BATCH 4 > > + > > +static void i40e_xmit_pkt_batch(struct i40e_ring *xdp_ring, struct xdp_desc *desc, > > + unsigned int *total_bytes) > > +{ > > + u16 ntu = xdp_ring->next_to_use; > > + struct i40e_tx_desc *tx_desc; > > + dma_addr_t dma; > > + u32 i; > > + > > +#pragma GCC unroll 4 > > + for (i = 0; i < PKTS_PER_BATCH; i++) { > > + dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, desc[i].addr); > > + xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma, desc[i].len); > > + > > + tx_desc = I40E_TX_DESC(xdp_ring, ntu++); > > + tx_desc->buffer_addr = cpu_to_le64(dma); > > + tx_desc->cmd_type_offset_bsz = build_ctob(I40E_TX_DESC_CMD_ICRC | > > + I40E_TX_DESC_CMD_EOP, > > + 0, desc[i].len, 0); > > + > > + *total_bytes += desc[i].len; > > + } > > + > > + xdp_ring->next_to_use = ntu; > > +} > > + > > +static void i40e_fill_tx_hw_ring(struct i40e_ring *xdp_ring, struct xdp_desc *descs, u32 nb_pkts, > > + unsigned int *total_bytes) > > +{ > > + u32 batched, leftover, i; > > + > > + batched = nb_pkts & ~(PKTS_PER_BATCH - 1); > > + leftover = nb_pkts & (PKTS_PER_BATCH - 1); > > + for (i = 0; i < batched; i += PKTS_PER_BATCH) > > + i40e_xmit_pkt_batch(xdp_ring, &descs[i], total_bytes); > > + for (i = batched; i < batched + leftover; i++) > > + i40e_xmit_pkt(xdp_ring, &descs[i], total_bytes); > > +} > > + > > +static void i40e_set_rs_bit(struct i40e_ring *xdp_ring) > > +{ > > + u16 ntu = xdp_ring->next_to_use ? xdp_ring->next_to_use - 1 : xdp_ring->count - 1; > > + struct i40e_tx_desc *tx_desc; > > + > > + tx_desc = I40E_TX_DESC(xdp_ring, ntu); > > + tx_desc->cmd_type_offset_bsz |= (I40E_TX_DESC_CMD_RS << I40E_TXD_QW1_CMD_SHIFT); > > +} > > + > > /** > > * i40e_xmit_zc - Performs zero-copy Tx AF_XDP > > * @xdp_ring: XDP Tx ring > > @@ -392,45 +464,30 @@ int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget) > > **/ > > static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > { > > - unsigned int sent_frames = 0, total_bytes = 0; > > - struct i40e_tx_desc *tx_desc = NULL; > > - struct xdp_desc desc; > > - dma_addr_t dma; > > - > > - while (budget-- > 0) { > > - if (!xsk_tx_peek_desc(xdp_ring->xsk_pool, &desc)) > > - break; > > - > > - dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, desc.addr); > > - xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma, > > - desc.len); > > - > > - tx_desc = I40E_TX_DESC(xdp_ring, xdp_ring->next_to_use); > > - tx_desc->buffer_addr = cpu_to_le64(dma); > > - tx_desc->cmd_type_offset_bsz = > > - build_ctob(I40E_TX_DESC_CMD_ICRC > > - | I40E_TX_DESC_CMD_EOP, > > - 0, desc.len, 0); > > - > > - sent_frames++; > > - total_bytes += desc.len; > > - > > - xdp_ring->next_to_use++; > > - if (xdp_ring->next_to_use == xdp_ring->count) > > - xdp_ring->next_to_use = 0; > > + struct xdp_desc *descs = xdp_ring->xsk_descs; > > + u32 nb_pkts, nb_processed = 0; > > + unsigned int total_bytes = 0; > > + > > + nb_pkts = xsk_tx_peek_release_desc_batch(xdp_ring->xsk_pool, descs, budget); > > + if (!nb_pkts) > > + return false; > > + > > + if (xdp_ring->next_to_use + nb_pkts >= xdp_ring->count) { > > + nb_processed = xdp_ring->count - xdp_ring->next_to_use; > > + i40e_fill_tx_hw_ring(xdp_ring, descs, nb_processed, &total_bytes); > > + xdp_ring->next_to_use = 0; > > } > > > > - if (tx_desc) { > > - /* Request an interrupt for the last frame and bump tail ptr. */ > > - tx_desc->cmd_type_offset_bsz |= (I40E_TX_DESC_CMD_RS << > > - I40E_TXD_QW1_CMD_SHIFT); > > - i40e_xdp_ring_update_tail(xdp_ring); > > + i40e_fill_tx_hw_ring(xdp_ring, &descs[nb_processed], nb_pkts - nb_processed, > > + &total_bytes); > > > > - xsk_tx_release(xdp_ring->xsk_pool); > > - i40e_update_tx_stats(xdp_ring, sent_frames, total_bytes); > > - } > > + /* Request an interrupt for the last frame and bump tail ptr. */ > > + i40e_set_rs_bit(xdp_ring); > > + i40e_xdp_ring_update_tail(xdp_ring); > > + > > + i40e_update_tx_stats(xdp_ring, nb_pkts, total_bytes); > > > > - return !!budget; > > + return true; > > } > > > > /** > > -- > > 2.7.4 > >