{"id":807126,"url":"http://patchwork.ozlabs.org/api/1.0/patches/807126/?format=json","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/1.0/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<150401747611.16384.8021135230122395742.stgit@firesoul>","date":"2017-08-29T14:37:56","name":"[net-next,4/7] xdp: separate xdp_redirect tracepoint in error case","commit_ref":null,"pull_url":null,"state":"accepted","archived":true,"hash":"9ee5117b936b8f84460fd959b147cd24087a88cf","submitter":{"id":13625,"url":"http://patchwork.ozlabs.org/api/1.0/people/13625/?format=json","name":"Jesper Dangaard Brouer","email":"brouer@redhat.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/1.0/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/150401747611.16384.8021135230122395742.stgit@firesoul/mbox/","series":[{"id":382,"url":"http://patchwork.ozlabs.org/api/1.0/series/382/?format=json","date":"2017-08-29T14:37:35","name":"XDP redirect tracepoints","version":1,"mbox":"http://patchwork.ozlabs.org/series/382/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/807126/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","ext-mx03.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx03.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=brouer@redhat.com"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xhWT60X57z9s7f\n\tfor ;\n\tWed, 30 Aug 2017 00:38:02 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1754541AbdH2OiA (ORCPT );\n\tTue, 29 Aug 2017 10:38:00 -0400","from mx1.redhat.com ([209.132.183.28]:57914 \"EHLO mx1.redhat.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1752746AbdH2Oh6 (ORCPT );\n\tTue, 29 Aug 2017 10:37:58 -0400","from smtp.corp.redhat.com\n\t(int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id A82DF7E424;\n\tTue, 29 Aug 2017 14:37:57 +0000 (UTC)","from firesoul.localdomain (ovpn-200-32.brq.redhat.com\n\t[10.40.200.32])\n\tby smtp.corp.redhat.com (Postfix) with ESMTP id 06FCC6FEF8;\n\tTue, 29 Aug 2017 14:37:57 +0000 (UTC)","from [192.168.5.1] (localhost [IPv6:::1])\n\tby firesoul.localdomain (Postfix) with ESMTP id 31A0330F12C9F;\n\tTue, 29 Aug 2017 16:37:56 +0200 (CEST)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com A82DF7E424","Subject":"[PATCH net-next 4/7] xdp: separate xdp_redirect tracepoint in error\n\tcase","From":"Jesper Dangaard Brouer ","To":"netdev@vger.kernel.org","Cc":"John Fastabend ,\n\tJesper Dangaard Brouer ","Date":"Tue, 29 Aug 2017 16:37:56 +0200","Message-ID":"<150401747611.16384.8021135230122395742.stgit@firesoul>","In-Reply-To":"<150401743083.16384.15778781741742858567.stgit@firesoul>","References":"<150401743083.16384.15778781741742858567.stgit@firesoul>","User-Agent":"StGit/0.17.1-dirty","MIME-Version":"1.0","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"7bit","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.13","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.27]);\n\tTue, 29 Aug 2017 14:37:57 +0000 (UTC)","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"There is a need to separate the xdp_redirect tracepoint into two\ntracepoints, for separating the error case from the normal forward\ncase.\n\nDue to the extreme speeds XDP is operating at, loading a tracepoint\nhave a measurable impact. Single core XDP REDIRECT (ethtool tuned\nrx-usecs 25) can do 13.7 Mpps forwarding, but loading a simple\nbpf_prog at the tracepoint (with a return 0) reduce perf to 10.2 Mpps\n(CPU E5-1650 v4 @ 3.60GHz, driver: ixgbe)\n\nThe overhead of loading a bpf-based tracepoint can be calculated to\ncost 25 nanosec ((1/13782002-1/10267937)*10^9 = -24.83 ns).\n\nUsing perf record on the tracepoint event, with a non-matching --filter\nexpression, the overhead is much larger. Performance drops to 8.3 Mpps,\ncost 48 nanosec ((1/13782002-1/8312497)*10^9 = -47.74))\n\nHaving a separate tracepoint for err cases, which should be less\nfrequent, allow running a continuous monitor for errors while not\naffecting the redirect forward performance (this have also been\nverified by measurements).\n\nSigned-off-by: Jesper Dangaard Brouer \n---\n include/trace/events/xdp.h | 22 ++++++++++++++++++----\n net/core/filter.c | 37 ++++++++++++++++++++++++-------------\n 2 files changed, 42 insertions(+), 17 deletions(-)","diff":"diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h\nindex 89eba564e199..1eebad55ebd4 100644\n--- a/include/trace/events/xdp.h\n+++ b/include/trace/events/xdp.h\n@@ -94,11 +94,25 @@ DEFINE_EVENT(xdp_redirect_template, xdp_redirect,\n \tTP_ARGS(dev, xdp, to_ifindex, err, map, map_index)\n );\n \n-#define _trace_xdp_redirect(dev, xdp, to, err)\t\\\n-\t trace_xdp_redirect(dev, xdp, to, err, NULL, 0);\n+DEFINE_EVENT(xdp_redirect_template, xdp_redirect_err,\n+\tTP_PROTO(const struct net_device *dev,\n+\t\t const struct bpf_prog *xdp,\n+\t\t int to_ifindex, int err,\n+\t\t const struct bpf_map *map, u32 map_index),\n+\tTP_ARGS(dev, xdp, to_ifindex, err, map, map_index)\n+);\n+\n+#define _trace_xdp_redirect(dev, xdp, to)\t\t\\\n+\t trace_xdp_redirect(dev, xdp, to, 0, NULL, 0);\n+\n+#define _trace_xdp_redirect_err(dev, xdp, to, err)\t\\\n+\t trace_xdp_redirect_err(dev, xdp, to, err, NULL, 0);\n+\n+#define trace_xdp_redirect_map(dev, xdp, fwd, map, idx)\t\\\n+\ttrace_xdp_redirect(dev, xdp, fwd ? fwd->ifindex : 0, 0, map, idx);\n \n-#define trace_xdp_redirect_map(dev, xdp, fwd, err, map, idx)\t\\\n-\ttrace_xdp_redirect(dev, xdp, fwd ? fwd->ifindex : 0, err, map, idx);\n+#define trace_xdp_redirect_map_err(dev, xdp, fwd, map, idx, err)\t\\\n+\ttrace_xdp_redirect_err(dev, xdp, fwd ? fwd->ifindex : 0, err, map, idx);\n \n #endif /* _TRACE_XDP_H */\n \ndiff --git a/net/core/filter.c b/net/core/filter.c\nindex 31eab77cc842..096e78de0b97 100644\n--- a/net/core/filter.c\n+++ b/net/core/filter.c\n@@ -2515,16 +2515,20 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,\n \tfwd = __dev_map_lookup_elem(map, index);\n \tif (!fwd) {\n \t\terr = -EINVAL;\n-\t\tgoto out;\n+\t\tgoto err;\n \t}\n \tif (ri->map_to_flush && ri->map_to_flush != map)\n \t\txdp_do_flush_map();\n \n \terr = __bpf_tx_xdp(fwd, map, xdp, index);\n-\tif (likely(!err))\n-\t\tri->map_to_flush = map;\n-out:\n-\ttrace_xdp_redirect_map(dev, xdp_prog, fwd, err, map, index);\n+\tif (unlikely(err))\n+\t\tgoto err;\n+\n+\tri->map_to_flush = map;\n+\ttrace_xdp_redirect_map(dev, xdp_prog, fwd, map, index);\n+\treturn 0;\n+err:\n+\ttrace_xdp_redirect_map_err(dev, xdp_prog, fwd, map, index, err);\n \treturn err;\n }\n \n@@ -2543,12 +2547,17 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,\n \tri->ifindex = 0;\n \tif (unlikely(!fwd)) {\n \t\terr = -EINVAL;\n-\t\tgoto out;\n+\t\tgoto err;\n \t}\n \n \terr = __bpf_tx_xdp(fwd, NULL, xdp, 0);\n-out:\n-\t_trace_xdp_redirect(dev, xdp_prog, index, err);\n+\tif (unlikely(err))\n+\t\tgoto err;\n+\n+\t_trace_xdp_redirect(dev, xdp_prog, index);\n+\treturn 0;\n+err:\n+\t_trace_xdp_redirect_err(dev, xdp_prog, index, err);\n \treturn err;\n }\n EXPORT_SYMBOL_GPL(xdp_do_redirect);\n@@ -2566,23 +2575,25 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,\n \tri->ifindex = 0;\n \tif (unlikely(!fwd)) {\n \t\terr = -EINVAL;\n-\t\tgoto out;\n+\t\tgoto err;\n \t}\n \n \tif (unlikely(!(fwd->flags & IFF_UP))) {\n \t\terr = -ENETDOWN;\n-\t\tgoto out;\n+\t\tgoto err;\n \t}\n \n \tlen = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;\n \tif (skb->len > len) {\n \t\terr = -EMSGSIZE;\n-\t\tgoto out;\n+\t\tgoto err;\n \t}\n \n \tskb->dev = fwd;\n-out:\n-\t_trace_xdp_redirect(dev, xdp_prog, index, err);\n+\t_trace_xdp_redirect(dev, xdp_prog, index);\n+\treturn 0;\n+err:\n+\t_trace_xdp_redirect_err(dev, xdp_prog, index, err);\n \treturn err;\n }\n EXPORT_SYMBOL_GPL(xdp_do_generic_redirect);\n","prefixes":["net-next","4/7"]}