From patchwork Tue May 12 19:24:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1288771 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=m11x9ly0; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49M7cJ244tz9sSW for ; Wed, 13 May 2020 05:47:12 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731118AbgELTrK (ORCPT ); Tue, 12 May 2020 15:47:10 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:28324 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731073AbgELTrJ (ORCPT ); Tue, 12 May 2020 15:47:09 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 04CJhaOb019306 for ; Tue, 12 May 2020 12:47:07 -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=jrGcGYevxkVpD8cFzVZazMFSjTBHwSqNFA25Sc2s7Fw=; b=m11x9ly0+S2jhv2jE646z9mFCujIhm1FDnAy9SWOH9Tdn6/7DwCVDj7cSH4hGZz1kKOK sUzWxsK3ArNgH0afcid7hj2yUJwV+Gng87hq+kb3BOTRxfl6uOVg90sBZtef0q5w/LOm BQsOBTXwMUgT7/qlb0flo237el1FwtGpnQ0= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3100wfrg70-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 12 May 2020 12:47:07 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Tue, 12 May 2020 12:47:06 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id E9A072EC317E; Tue, 12 May 2020 12:47:04 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko , John Fastabend , Yonghong Song Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v3 bpf-next 4/4] selftest/bpf: add BPF triggering benchmark Date: Tue, 12 May 2020 12:24:45 -0700 Message-ID: <20200512192445.2351848-5-andriin@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200512192445.2351848-1-andriin@fb.com> References: <20200512192445.2351848-1-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=2020-05-12_07:2020-05-11,2020-05-12 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 spamscore=0 lowpriorityscore=0 impostorscore=0 suspectscore=9 phishscore=0 priorityscore=1501 clxscore=1015 bulkscore=0 adultscore=0 malwarescore=0 cotscore=-2147483648 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005120149 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@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 (using benchs/run_bench_trigger.sh script): 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. Acked-by: John Fastabend Acked-by: Yonghong Song Signed-off-by: Andrii Nakryiko --- tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/bench.c | 12 ++ .../selftests/bpf/benchs/bench_trigger.c | 167 ++++++++++++++++++ .../selftests/bpf/benchs/run_bench_trigger.sh | 9 + .../selftests/bpf/progs/trigger_bench.c | 47 +++++ 5 files changed, 238 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/benchs/bench_trigger.c create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_trigger.sh 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 3c43d4eceba8..352d17a16bae 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -411,11 +411,13 @@ $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(call msg,CC,,$@) $(CC) $(CFLAGS) -c $(filter %.c,$^) $(LDLIBS) -o $@ $(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h +$(OUTPUT)/bench_trigger.o: $(OUTPUT)/trigger_bench.skel.h $(OUTPUT)/bench.o: bench.h testing_helpers.h $(OUTPUT)/bench: LDLIBS += -lm $(OUTPUT)/bench: $(OUTPUT)/bench.o $(OUTPUT)/testing_helpers.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 c9e8b7dbaf66..8c0dfbfe6088 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -304,6 +304,12 @@ 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, @@ -315,6 +321,12 @@ 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/benchs/bench_trigger.c b/tools/testing/selftests/bpf/benchs/bench_trigger.c new file mode 100644 index 000000000000..49c22832f216 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/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/benchs/run_bench_trigger.sh b/tools/testing/selftests/bpf/benchs/run_bench_trigger.sh new file mode 100755 index 000000000000..78e83f243294 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/run_bench_trigger.sh @@ -0,0 +1,9 @@ +#!/bin/bash + +set -eufo pipefail + +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 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; +}