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=-10.0 required=3.0 tests=BAYES_00, 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 B30BCC43461 for ; Fri, 4 Sep 2020 15:35:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9540F2074D for ; Fri, 4 Sep 2020 15:35:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726292AbgIDPf4 convert rfc822-to-8bit (ORCPT ); Fri, 4 Sep 2020 11:35:56 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:50326 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726259AbgIDPfz (ORCPT ); Fri, 4 Sep 2020 11:35:55 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-311-kGKBJwK8OvGiLSRrqb5OtA-1; Fri, 04 Sep 2020 11:35:52 -0400 X-MC-Unique: kGKBJwK8OvGiLSRrqb5OtA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6FC341007474; Fri, 4 Sep 2020 15:35:50 +0000 (UTC) Received: from carbon (unknown [10.40.208.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id CF38465C74; Fri, 4 Sep 2020 15:35:42 +0000 (UTC) Date: Fri, 4 Sep 2020 17:35:40 +0200 From: Jesper Dangaard Brouer To: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= Cc: brouer@redhat.com, ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, bpf@vger.kernel.org, =?UTF-8?B?QmrDtnJuIFTDtnBl?= =?UTF-8?B?bA==?= , magnus.karlsson@intel.com, davem@davemloft.net, kuba@kernel.org, john.fastabend@gmail.com, intel-wired-lan@lists.osuosl.org Subject: Re: [PATCH bpf-next 6/6] ixgbe, xsk: finish napi loop if AF_XDP Rx queue is full Message-ID: <20200904173540.3a617eee@carbon> In-Reply-To: <20200904135332.60259-7-bjorn.topel@gmail.com> References: <20200904135332.60259-1-bjorn.topel@gmail.com> <20200904135332.60259-7-bjorn.topel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, 4 Sep 2020 15:53:31 +0200 Björn Töpel wrote: > From: Björn Töpel > > Make the AF_XDP zero-copy path aware that the reason for redirect > failure was due to full Rx queue. If so, exit the napi loop as soon as > possible (exit the softirq processing), so that the userspace AF_XDP > process can hopefully empty the Rx queue. This mainly helps the "one > core scenario", where the userland process and Rx softirq processing > is on the same core. > > Note that the early exit can only be performed if the "need wakeup" > feature is enabled, because otherwise there is no notification > mechanism available from the kernel side. > > This requires that the driver starts using the newly introduced > xdp_do_redirect_ext() and xsk_do_redirect_rx_full() functions. > > Signed-off-by: Björn Töpel > --- > drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 23 ++++++++++++++------ > 1 file changed, 16 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > index 3771857cf887..a4aebfd986b3 100644 > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > @@ -93,9 +93,11 @@ int ixgbe_xsk_pool_setup(struct ixgbe_adapter *adapter, > > static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter, > struct ixgbe_ring *rx_ring, > - struct xdp_buff *xdp) > + struct xdp_buff *xdp, > + bool *early_exit) > { > int err, result = IXGBE_XDP_PASS; > + enum bpf_map_type map_type; > struct bpf_prog *xdp_prog; > struct xdp_frame *xdpf; > u32 act; > @@ -116,8 +118,13 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter, > result = ixgbe_xmit_xdp_ring(adapter, xdpf); > break; > case XDP_REDIRECT: > - err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); > - result = !err ? IXGBE_XDP_REDIR : IXGBE_XDP_CONSUMED; > + err = xdp_do_redirect_ext(rx_ring->netdev, xdp, xdp_prog, &map_type); > + if (err) { > + *early_exit = xsk_do_redirect_rx_full(err, map_type); Have you tried calling xdp_do_flush (that calls __xsk_map_flush()) and (I guess) xsk_set_rx_need_wakeup() here, instead of stopping the loop? (Or doing this in xsk core). Looking at the code, the AF_XDP frames are "published" in the queue rather late for AF_XDP. Maybe in an orthogonal optimization, have you considered "publishing" the ring producer when e.g. the queue is half-full? > + result = IXGBE_XDP_CONSUMED; > + } else { > + result = IXGBE_XDP_REDIR; > + } > break; > default: > bpf_warn_invalid_xdp_action(act); > @@ -235,8 +242,8 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > unsigned int total_rx_bytes = 0, total_rx_packets = 0; > struct ixgbe_adapter *adapter = q_vector->adapter; > u16 cleaned_count = ixgbe_desc_unused(rx_ring); > + bool early_exit = false, failure = false; > unsigned int xdp_res, xdp_xmit = 0; > - bool failure = false; > struct sk_buff *skb; > > while (likely(total_rx_packets < budget)) { > @@ -288,7 +295,7 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > > bi->xdp->data_end = bi->xdp->data + size; > xsk_buff_dma_sync_for_cpu(bi->xdp, rx_ring->xsk_pool); > - xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp); > + xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp, &early_exit); > > if (xdp_res) { > if (xdp_res & (IXGBE_XDP_TX | IXGBE_XDP_REDIR)) > @@ -302,6 +309,8 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > > cleaned_count++; > ixgbe_inc_ntc(rx_ring); > + if (early_exit) > + break; > continue; > } > > @@ -346,12 +355,12 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > q_vector->rx.total_bytes += total_rx_bytes; > > if (xsk_uses_need_wakeup(rx_ring->xsk_pool)) { > - if (failure || rx_ring->next_to_clean == rx_ring->next_to_use) > + if (early_exit || failure || rx_ring->next_to_clean == rx_ring->next_to_use) > xsk_set_rx_need_wakeup(rx_ring->xsk_pool); > else > xsk_clear_rx_need_wakeup(rx_ring->xsk_pool); > > - return (int)total_rx_packets; > + return early_exit ? 0 : (int)total_rx_packets; > } > return failure ? budget : (int)total_rx_packets; > } -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Date: Fri, 4 Sep 2020 17:35:40 +0200 Subject: [Intel-wired-lan] [PATCH bpf-next 6/6] ixgbe, xsk: finish napi loop if AF_XDP Rx queue is full In-Reply-To: <20200904135332.60259-7-bjorn.topel@gmail.com> References: <20200904135332.60259-1-bjorn.topel@gmail.com> <20200904135332.60259-7-bjorn.topel@gmail.com> Message-ID: <20200904173540.3a617eee@carbon> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On Fri, 4 Sep 2020 15:53:31 +0200 Bj?rn T?pel wrote: > From: Bj?rn T?pel > > Make the AF_XDP zero-copy path aware that the reason for redirect > failure was due to full Rx queue. If so, exit the napi loop as soon as > possible (exit the softirq processing), so that the userspace AF_XDP > process can hopefully empty the Rx queue. This mainly helps the "one > core scenario", where the userland process and Rx softirq processing > is on the same core. > > Note that the early exit can only be performed if the "need wakeup" > feature is enabled, because otherwise there is no notification > mechanism available from the kernel side. > > This requires that the driver starts using the newly introduced > xdp_do_redirect_ext() and xsk_do_redirect_rx_full() functions. > > Signed-off-by: Bj?rn T?pel > --- > drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 23 ++++++++++++++------ > 1 file changed, 16 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > index 3771857cf887..a4aebfd986b3 100644 > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c > @@ -93,9 +93,11 @@ int ixgbe_xsk_pool_setup(struct ixgbe_adapter *adapter, > > static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter, > struct ixgbe_ring *rx_ring, > - struct xdp_buff *xdp) > + struct xdp_buff *xdp, > + bool *early_exit) > { > int err, result = IXGBE_XDP_PASS; > + enum bpf_map_type map_type; > struct bpf_prog *xdp_prog; > struct xdp_frame *xdpf; > u32 act; > @@ -116,8 +118,13 @@ static int ixgbe_run_xdp_zc(struct ixgbe_adapter *adapter, > result = ixgbe_xmit_xdp_ring(adapter, xdpf); > break; > case XDP_REDIRECT: > - err = xdp_do_redirect(rx_ring->netdev, xdp, xdp_prog); > - result = !err ? IXGBE_XDP_REDIR : IXGBE_XDP_CONSUMED; > + err = xdp_do_redirect_ext(rx_ring->netdev, xdp, xdp_prog, &map_type); > + if (err) { > + *early_exit = xsk_do_redirect_rx_full(err, map_type); Have you tried calling xdp_do_flush (that calls __xsk_map_flush()) and (I guess) xsk_set_rx_need_wakeup() here, instead of stopping the loop? (Or doing this in xsk core). Looking at the code, the AF_XDP frames are "published" in the queue rather late for AF_XDP. Maybe in an orthogonal optimization, have you considered "publishing" the ring producer when e.g. the queue is half-full? > + result = IXGBE_XDP_CONSUMED; > + } else { > + result = IXGBE_XDP_REDIR; > + } > break; > default: > bpf_warn_invalid_xdp_action(act); > @@ -235,8 +242,8 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > unsigned int total_rx_bytes = 0, total_rx_packets = 0; > struct ixgbe_adapter *adapter = q_vector->adapter; > u16 cleaned_count = ixgbe_desc_unused(rx_ring); > + bool early_exit = false, failure = false; > unsigned int xdp_res, xdp_xmit = 0; > - bool failure = false; > struct sk_buff *skb; > > while (likely(total_rx_packets < budget)) { > @@ -288,7 +295,7 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > > bi->xdp->data_end = bi->xdp->data + size; > xsk_buff_dma_sync_for_cpu(bi->xdp, rx_ring->xsk_pool); > - xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp); > + xdp_res = ixgbe_run_xdp_zc(adapter, rx_ring, bi->xdp, &early_exit); > > if (xdp_res) { > if (xdp_res & (IXGBE_XDP_TX | IXGBE_XDP_REDIR)) > @@ -302,6 +309,8 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > > cleaned_count++; > ixgbe_inc_ntc(rx_ring); > + if (early_exit) > + break; > continue; > } > > @@ -346,12 +355,12 @@ int ixgbe_clean_rx_irq_zc(struct ixgbe_q_vector *q_vector, > q_vector->rx.total_bytes += total_rx_bytes; > > if (xsk_uses_need_wakeup(rx_ring->xsk_pool)) { > - if (failure || rx_ring->next_to_clean == rx_ring->next_to_use) > + if (early_exit || failure || rx_ring->next_to_clean == rx_ring->next_to_use) > xsk_set_rx_need_wakeup(rx_ring->xsk_pool); > else > xsk_clear_rx_need_wakeup(rx_ring->xsk_pool); > > - return (int)total_rx_packets; > + return early_exit ? 0 : (int)total_rx_packets; > } > return failure ? budget : (int)total_rx_packets; > } -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer