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GET /api/patches/807126/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 807126,
    "url": "http://patchwork.ozlabs.org/api/patches/807126/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/netdev/patch/150401747611.16384.8021135230122395742.stgit@firesoul/",
    "project": {
        "id": 7,
        "url": "http://patchwork.ozlabs.org/api/projects/7/?format=api",
        "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,
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<150401747611.16384.8021135230122395742.stgit@firesoul>",
    "list_archive_url": null,
    "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/people/13625/?format=api",
        "name": "Jesper Dangaard Brouer",
        "email": "brouer@redhat.com"
    },
    "delegate": {
        "id": 34,
        "url": "http://patchwork.ozlabs.org/api/users/34/?format=api",
        "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/series/382/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/netdev/list/?series=382",
            "date": "2017-08-29T14:37:35",
            "name": "XDP redirect tracepoints",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/382/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/807126/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/807126/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<netdev-owner@vger.kernel.org>",
        "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=<UNKNOWN>)",
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            "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 <patchwork-incoming@ozlabs.org>;\n\tWed, 30 Aug 2017 00:38:02 +1000 (AEST)",
            "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1754541AbdH2OiA (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\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 <rfc822;netdev@vger.kernel.org>);\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 <brouer@redhat.com>",
        "To": "netdev@vger.kernel.org",
        "Cc": "John Fastabend <john.fastabend@gmail.com>,\n\tJesper Dangaard Brouer <brouer@redhat.com>",
        "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": "<netdev.vger.kernel.org>",
        "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 <brouer@redhat.com>\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"
    ]
}