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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 75FD3C432C0 for ; Fri, 22 Nov 2019 01:15:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B8042068D for ; Fri, 22 Nov 2019 01:15:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574385320; bh=rK8nTdE+EWBGgOxF6Sdvdh2Zxa0SQLc0Z0VnPkrS6sw=; h=From:To:CC:Subject:Date:List-ID:From; b=2cnE+cRaxtEKx922KhnAUJh6hrRMQA9FYn0XUaFFHXsgoJ/bwwpFsXmKSOWiHWFJk aN1AxDiriI7dv9/GWZwAVVrBr29JTUfxH/R+tIvvy6tB2hGJV9HrocTDpNo8MjS496 5SdDJULETwom5lYKv5FYJBekfuQ/4//SwP/XwAVg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726335AbfKVBPT convert rfc822-to-8bit (ORCPT ); Thu, 21 Nov 2019 20:15:19 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:15244 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726265AbfKVBPT (ORCPT ); Thu, 21 Nov 2019 20:15:19 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xAM1EGSR008690 for ; Thu, 21 Nov 2019 17:15:18 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2wda3vmcgg-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 21 Nov 2019 17:15:17 -0800 Received: from 2401:db00:30:6007:face:0:1:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Thu, 21 Nov 2019 17:15:16 -0800 Received: by devbig007.ftw2.facebook.com (Postfix, from userid 572438) id 4D8BD760B98; Thu, 21 Nov 2019 17:15:15 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Alexei Starovoitov Smtp-Origin-Hostname: devbig007.ftw2.facebook.com To: CC: , , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next] selftests/bpf: Add BPF trampoline performance test Date: Thu, 21 Nov 2019 17:15:15 -0800 Message-ID: <20191122011515.255371-1-ast@kernel.org> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-11-21_07:2019-11-21,2019-11-21 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 adultscore=0 mlxlogscore=976 lowpriorityscore=0 priorityscore=1501 impostorscore=0 suspectscore=1 bulkscore=0 clxscore=1015 mlxscore=0 spamscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911220008 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add a test that benchmarks different ways of attaching BPF program to a kernel function. Here are the results for 2.4Ghz x86 cpu on a kernel without mitigations: $ ./test_progs -n 49 -v|grep events task_rename base 2743K events per sec task_rename kprobe 2419K events per sec task_rename kretprobe 1876K events per sec task_rename raw_tp 2578K events per sec task_rename fentry 2710K events per sec task_rename fexit 2685K events per sec On a kernel with retpoline: $ ./test_progs -n 49 -v|grep events task_rename base 2401K events per sec task_rename kprobe 1930K events per sec task_rename kretprobe 1485K events per sec task_rename raw_tp 2053K events per sec task_rename fentry 2351K events per sec task_rename fexit 2185K events per sec All 5 approaches: - kprobe/kretprobe in __set_task_comm() - raw tracepoint in trace_task_rename() - fentry/fexit in __set_task_comm() are roughly equivalent. __set_task_comm() by itself is quite fast, so any extra instructions add up. Until BPF trampoline was introduced the fastest mechanism was raw tracepoint. kprobe via ftrace was second best. kretprobe is slow due to trap. New fentry/fexit methods via BPF trampoline are clearly the fastest and the difference is more pronounced with retpoline on, since BPF trampoline doesn't use indirect jumps. Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/test_overhead.c | 142 ++++++++++++++++++ .../selftests/bpf/progs/test_overhead.c | 43 ++++++ 2 files changed, 185 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/test_overhead.c create mode 100644 tools/testing/selftests/bpf/progs/test_overhead.c diff --git a/tools/testing/selftests/bpf/prog_tests/test_overhead.c b/tools/testing/selftests/bpf/prog_tests/test_overhead.c new file mode 100644 index 000000000000..c32aa28bd93f --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/test_overhead.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2019 Facebook */ +#define _GNU_SOURCE +#include +#include + +#define MAX_CNT 100000 + +static __u64 time_get_ns(void) +{ + struct timespec ts; + + clock_gettime(CLOCK_MONOTONIC, &ts); + return ts.tv_sec * 1000000000ull + ts.tv_nsec; +} + +static int test_task_rename(const char *prog) +{ + int i, fd, duration = 0, err; + char buf[] = "test\n"; + __u64 start_time; + + fd = open("/proc/self/comm", O_WRONLY|O_TRUNC); + if (CHECK(fd < 0, "open /proc", "err %d", errno)) + return -1; + start_time = time_get_ns(); + for (i = 0; i < MAX_CNT; i++) { + err = write(fd, buf, sizeof(buf)); + if (err < 0) { + CHECK(err < 0, "task rename", "err %d", errno); + close(fd); + return -1; + } + } + printf("task_rename %s\t%lluK events per sec\n", prog, + MAX_CNT * 1000000ll / (time_get_ns() - start_time)); + close(fd); + return 0; +} + +static void test_run(const char *prog) +{ + test_task_rename(prog); +} + +static void setaffinity(void) +{ + cpu_set_t cpuset; + int cpu = 0; + + CPU_ZERO(&cpuset); + CPU_SET(cpu, &cpuset); + sched_setaffinity(0, sizeof(cpuset), &cpuset); +} + +void test_test_overhead(void) +{ + const char *kprobe_name = "kprobe/__set_task_comm"; + const char *kretprobe_name = "kretprobe/__set_task_comm"; + const char *raw_tp_name = "raw_tp/task_rename"; + const char *fentry_name = "fentry/__set_task_comm"; + const char *fexit_name = "fexit/__set_task_comm"; + const char *kprobe_func = "__set_task_comm"; + struct bpf_program *kprobe_prog, *kretprobe_prog, *raw_tp_prog; + struct bpf_program *fentry_prog, *fexit_prog; + struct bpf_object *obj; + struct bpf_link *link; + int err, duration = 0; + + obj = bpf_object__open_file("./test_overhead.o", NULL); + if (CHECK(IS_ERR(obj), "obj_open_file", "err %ld\n", PTR_ERR(obj))) + return; + + kprobe_prog = bpf_object__find_program_by_title(obj, kprobe_name); + if (CHECK(!kprobe_prog, "find_probe", + "prog '%s' not found\n", kprobe_name)) + goto cleanup; + kretprobe_prog = bpf_object__find_program_by_title(obj, kretprobe_name); + if (CHECK(!kretprobe_prog, "find_probe", + "prog '%s' not found\n", kretprobe_name)) + goto cleanup; + raw_tp_prog = bpf_object__find_program_by_title(obj, raw_tp_name); + if (CHECK(!raw_tp_prog, "find_probe", + "prog '%s' not found\n", raw_tp_name)) + goto cleanup; + fentry_prog = bpf_object__find_program_by_title(obj, fentry_name); + if (CHECK(!fentry_prog, "find_probe", + "prog '%s' not found\n", fentry_name)) + goto cleanup; + fexit_prog = bpf_object__find_program_by_title(obj, fexit_name); + if (CHECK(!fexit_prog, "find_probe", + "prog '%s' not found\n", fexit_name)) + goto cleanup; + + err = bpf_object__load(obj); + if (CHECK(err, "obj_load", "err %d\n", err)) + goto cleanup; + + setaffinity(); + + /* base line run */ + test_run("base"); + + /* attach kprobe */ + link = bpf_program__attach_kprobe(kprobe_prog, false /* retprobe */, + kprobe_func); + if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link))) + goto cleanup; + test_run("kprobe"); + bpf_link__destroy(link); + + /* attach kretprobe */ + link = bpf_program__attach_kprobe(kretprobe_prog, true /* retprobe */, + kprobe_func); + if (CHECK(IS_ERR(link), "attach kretprobe", "err %ld\n", PTR_ERR(link))) + goto cleanup; + test_run("kretprobe"); + bpf_link__destroy(link); + + /* attach raw_tp */ + link = bpf_program__attach_raw_tracepoint(raw_tp_prog, "task_rename"); + if (CHECK(IS_ERR(link), "attach fentry", "err %ld\n", PTR_ERR(link))) + goto cleanup; + test_run("raw_tp"); + bpf_link__destroy(link); + + /* attach fentry */ + link = bpf_program__attach_trace(fentry_prog); + if (CHECK(IS_ERR(link), "attach fentry", "err %ld\n", PTR_ERR(link))) + goto cleanup; + test_run("fentry"); + bpf_link__destroy(link); + + /* attach fexit */ + link = bpf_program__attach_trace(fexit_prog); + if (CHECK(IS_ERR(link), "attach fexit", "err %ld\n", PTR_ERR(link))) + goto cleanup; + test_run("fexit"); + bpf_link__destroy(link); +cleanup: + bpf_object__close(obj); +} diff --git a/tools/testing/selftests/bpf/progs/test_overhead.c b/tools/testing/selftests/bpf/progs/test_overhead.c new file mode 100644 index 000000000000..ef06b2693f96 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_overhead.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019 Facebook */ +#include +#include "bpf_helpers.h" +#include "bpf_tracing.h" + +SEC("kprobe/__set_task_comm") +int prog1(struct pt_regs *ctx) +{ + return 0; +} + +SEC("kretprobe/__set_task_comm") +int prog2(struct pt_regs *ctx) +{ + return 0; +} + +SEC("raw_tp/task_rename") +int prog3(struct bpf_raw_tracepoint_args *ctx) +{ + return 0; +} + +struct __set_task_comm_args { + struct task_struct *tsk; + const char *buf; + ku8 exec; +}; + +SEC("fentry/__set_task_comm") +int prog4(struct __set_task_comm_args *ctx) +{ + return 0; +} + +SEC("fexit/__set_task_comm") +int prog5(struct __set_task_comm_args *ctx) +{ + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.23.0