From patchwork Fri May 8 07:05:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 219638 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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 4BF99C47247 for ; Fri, 8 May 2020 07:06:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AD7E20735 for ; Fri, 8 May 2020 07:06:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="cEMf/63d" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726948AbgEHHGK (ORCPT ); Fri, 8 May 2020 03:06:10 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:10046 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726926AbgEHHGJ (ORCPT ); Fri, 8 May 2020 03:06:09 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 048762k6020938 for ; Fri, 8 May 2020 00:06:08 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=facebook; bh=ZS1oDI2Et4SaZ9MaBPmVfnOuVL4IBzddh0+JB1hg0P4=; b=cEMf/63d1jgpouVbinfszTMSnf+X5BDW5k2Hdj3Zg5SJcndU2WBFqUKA2IBaCFR/Dytp Kxjz2VLs9Mf2ZcfwEjjfKll0xPv+cpEHOHBIHT4V2FC79QoDoBnZcNBwCVX/MiS33H26 q48FwxTb2x1XIFNX/ld2c9j+hmuInxjFT0U= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 30vtdfa52w-9 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 08 May 2020 00:06:08 -0700 Received: from intmgw002.03.ash8.facebook.com (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 15.1.1847.3; Fri, 8 May 2020 00:05:57 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 53A602EC3844; Fri, 8 May 2020 00:05:56 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next 3/3] selftest/bpf: add BPF triggring benchmark Date: Fri, 8 May 2020 00:05:48 -0700 Message-ID: <20200508070548.2358701-4-andriin@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200508070548.2358701-1-andriin@fb.com> References: <20200508070548.2358701-1-andriin@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.676 definitions=2020-05-08_08:2020-05-07,2020-05-08 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 impostorscore=0 suspectscore=8 mlxlogscore=999 clxscore=1015 phishscore=0 adultscore=0 malwarescore=0 lowpriorityscore=0 mlxscore=0 spamscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005080061 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org It is sometimes desirable to be able to trigger BPF program from user-space with minimal overhead. sys_enter would seem to be a good candidate, yet in a lot of cases there will be a lot of noise from syscalls triggered by other processes on the system. So while searching for low-overhead alternative, I've stumbled upon getpgid() syscall, which seems to be specific enough to not suffer from accidental syscall by other apps. This set of benchmarks compares tp, raw_tp w/ filtering by syscall ID, kprobe, fentry and fmod_ret with returning error (so that syscall would not be executed), to determine the lowest-overhead way. Here are results on my machine: $ for i in base tp rawtp kprobe fentry fmodret; \ do \ summary=$(sudo ./bench -w2 -d5 -a trig-$i | \ tail -n1 | cut -d'(' -f1 | cut -d' ' -f3- ) && \ printf "%-10s: %s\n" $i "$summary"; \ done base : 9.200 ± 0.319M/s tp : 6.690 ± 0.125M/s rawtp : 8.571 ± 0.214M/s kprobe : 6.431 ± 0.048M/s fentry : 8.955 ± 0.241M/s fmodret : 8.903 ± 0.135M/s So it seems like fmodret doesn't give much benefit for such lightweight syscall. Raw tracepoint is pretty decent despite additional filtering logic, but it will be called for any other syscall in the system, which rules it out. Fentry, though, seems to be adding the least amoung of overhead and achieves 97.3% of performance of baseline no-BPF-attached syscall. Using getpgid() seems to be preferable to set_task_comm() approach from test_overhead, as it's about 2.35x faster in a baseline performance. Signed-off-by: Andrii Nakryiko --- tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/bench.c | 12 ++ tools/testing/selftests/bpf/bench_trigger.c | 167 ++++++++++++++++++ .../selftests/bpf/progs/trigger_bench.c | 47 +++++ 4 files changed, 229 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/bench_trigger.c create mode 100644 tools/testing/selftests/bpf/progs/trigger_bench.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 275c5873a75f..a7391cccd3d2 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -409,10 +409,12 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ) $(OUTPUT)/bench.o: bench.h $(OUTPUT)/bench_count.o: bench.h $(OUTPUT)/bench_rename.o: bench.h $(OUTPUT)/test_overhead.skel.h +$(OUTPUT)/bench_trigger.o: bench.h $(OUTPUT)/trigger_bench.skel.h $(OUTPUT)/bench: LDLIBS += -lm $(OUTPUT)/bench: $(OUTPUT)/bench.o \ $(OUTPUT)/bench_count.o \ - $(OUTPUT)/bench_rename.o + $(OUTPUT)/bench_rename.o \ + $(OUTPUT)/bench_trigger.o $(call msg,BINARY,,$@) $(CC) $(LDFLAGS) -o $@ $(filter %.a %.o,$^) $(LDLIBS) diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index 6ce4002612c8..d74ff2ea303d 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -253,6 +253,12 @@ extern const struct bench bench_rename_rawtp; extern const struct bench bench_rename_fentry; extern const struct bench bench_rename_fexit; extern const struct bench bench_rename_fmodret; +extern const struct bench bench_trig_base; +extern const struct bench bench_trig_tp; +extern const struct bench bench_trig_rawtp; +extern const struct bench bench_trig_kprobe; +extern const struct bench bench_trig_fentry; +extern const struct bench bench_trig_fmodret; static const struct bench *benchs[] = { &bench_count_global, @@ -264,6 +270,12 @@ static const struct bench *benchs[] = { &bench_rename_fentry, &bench_rename_fexit, &bench_rename_fmodret, + &bench_trig_base, + &bench_trig_tp, + &bench_trig_rawtp, + &bench_trig_kprobe, + &bench_trig_fentry, + &bench_trig_fmodret, }; static void setup_benchmark() diff --git a/tools/testing/selftests/bpf/bench_trigger.c b/tools/testing/selftests/bpf/bench_trigger.c new file mode 100644 index 000000000000..49c22832f216 --- /dev/null +++ b/tools/testing/selftests/bpf/bench_trigger.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2020 Facebook */ +#include "bench.h" +#include "trigger_bench.skel.h" + +/* BPF triggering benchmarks */ +static struct trigger_ctx { + struct trigger_bench *skel; +} ctx; + +static struct counter base_hits; + +static void trigger_validate() +{ + if (env.consumer_cnt != 1) { + fprintf(stderr, "benchmark doesn't support multi-consumer!\n"); + exit(1); + } +} + +static void *trigger_base_producer(void *input) +{ + while (true) { + (void)syscall(__NR_getpgid); + atomic_inc(&base_hits.value); + } + return NULL; +} + +static void trigger_base_measure(struct bench_res *res) +{ + res->hits = atomic_swap(&base_hits.value, 0); +} + +static void *trigger_producer(void *input) +{ + while (true) + (void)syscall(__NR_getpgid); + return NULL; +} + +static void trigger_measure(struct bench_res *res) +{ + res->hits = atomic_swap(&ctx.skel->bss->hits, 0); +} + +static void setup_ctx() +{ + setup_libbpf(); + + ctx.skel = trigger_bench__open_and_load(); + if (!ctx.skel) { + fprintf(stderr, "failed to open skeleton\n"); + exit(1); + } +} + +static void attach_bpf(struct bpf_program *prog) +{ + struct bpf_link *link; + + link = bpf_program__attach(prog); + if (IS_ERR(link)) { + fprintf(stderr, "failed to attach program!\n"); + exit(1); + } +} + +static void trigger_tp_setup() +{ + setup_ctx(); + attach_bpf(ctx.skel->progs.bench_trigger_tp); +} + +static void trigger_rawtp_setup() +{ + setup_ctx(); + attach_bpf(ctx.skel->progs.bench_trigger_raw_tp); +} + +static void trigger_kprobe_setup() +{ + setup_ctx(); + attach_bpf(ctx.skel->progs.bench_trigger_kprobe); +} + +static void trigger_fentry_setup() +{ + setup_ctx(); + attach_bpf(ctx.skel->progs.bench_trigger_fentry); +} + +static void trigger_fmodret_setup() +{ + setup_ctx(); + attach_bpf(ctx.skel->progs.bench_trigger_fmodret); +} + +static void *trigger_consumer(void *input) +{ + return NULL; +} + +const struct bench bench_trig_base = { + .name = "trig-base", + .validate = trigger_validate, + .producer_thread = trigger_base_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_base_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_trig_tp = { + .name = "trig-tp", + .validate = trigger_validate, + .setup = trigger_tp_setup, + .producer_thread = trigger_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_trig_rawtp = { + .name = "trig-rawtp", + .validate = trigger_validate, + .setup = trigger_rawtp_setup, + .producer_thread = trigger_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_trig_kprobe = { + .name = "trig-kprobe", + .validate = trigger_validate, + .setup = trigger_kprobe_setup, + .producer_thread = trigger_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_trig_fentry = { + .name = "trig-fentry", + .validate = trigger_validate, + .setup = trigger_fentry_setup, + .producer_thread = trigger_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_trig_fmodret = { + .name = "trig-fmodret", + .validate = trigger_validate, + .setup = trigger_fmodret_setup, + .producer_thread = trigger_producer, + .consumer_thread = trigger_consumer, + .measure = trigger_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; diff --git a/tools/testing/selftests/bpf/progs/trigger_bench.c b/tools/testing/selftests/bpf/progs/trigger_bench.c new file mode 100644 index 000000000000..8b36b6640e7e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/trigger_bench.c @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook + +#include +#include +#include +#include + +char _license[] SEC("license") = "GPL"; + +long hits = 0; + +SEC("tp/syscalls/sys_enter_getpgid") +int bench_trigger_tp(void *ctx) +{ + __sync_add_and_fetch(&hits, 1); + return 0; +} + +SEC("raw_tp/sys_enter") +int BPF_PROG(bench_trigger_raw_tp, struct pt_regs *regs, long id) +{ + if (id == __NR_getpgid) + __sync_add_and_fetch(&hits, 1); + return 0; +} + +SEC("kprobe/__x64_sys_getpgid") +int bench_trigger_kprobe(void *ctx) +{ + __sync_add_and_fetch(&hits, 1); + return 0; +} + +SEC("fentry/__x64_sys_getpgid") +int bench_trigger_fentry(void *ctx) +{ + __sync_add_and_fetch(&hits, 1); + return 0; +} + +SEC("fmod_ret/__x64_sys_getpgid") +int bench_trigger_fmodret(void *ctx) +{ + __sync_add_and_fetch(&hits, 1); + return -22; +}