From patchwork Thu Apr 14 09:07:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Chen X-Patchwork-Id: 12813151 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 107F5C4332F for ; Thu, 14 Apr 2022 09:02:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241383AbiDNJEZ (ORCPT ); Thu, 14 Apr 2022 05:04:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241625AbiDNJCy (ORCPT ); Thu, 14 Apr 2022 05:02:54 -0400 Received: from 189.cn (ptr.189.cn [183.61.185.101]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D8F0633B; Thu, 14 Apr 2022 02:00:28 -0700 (PDT) HMM_SOURCE_IP: 10.64.8.43:52594.698421431 HMM_ATTACHE_NUM: 0000 HMM_SOURCE_TYPE: SMTP Received: from clientip-123.150.8.43 (unknown [10.64.8.43]) by 189.cn (HERMES) with SMTP id 7262B100180; Thu, 14 Apr 2022 17:00:26 +0800 (CST) Received: from ([123.150.8.43]) by gateway-153622-dep-749df8664c-nmrf6 with ESMTP id 89fc0cdd849b4fa5b64c6882a9cc62ac for ast@kernel.org; Thu, 14 Apr 2022 17:00:27 CST X-Transaction-ID: 89fc0cdd849b4fa5b64c6882a9cc62ac X-Real-From: chensong_2000@189.cn X-Receive-IP: 123.150.8.43 X-MEDUSA-Status: 0 Sender: chensong_2000@189.cn From: Song Chen To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Song Chen Subject: [RFC PATCH 1/1] sample: bpf: introduce irqlat Date: Thu, 14 Apr 2022 17:07:35 +0800 Message-Id: <1649927255-19036-1-git-send-email-chensong_2000@189.cn> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC irqlat presents max, min and avg value of time consumed in irq handling for each cpu, from irq_handler_entry to irq_handler_exit. engineers can run it to evaluate the performance of irq handling, especially for RT system. Signed-off-by: Song Chen --- samples/bpf/.gitignore | 1 + samples/bpf/Makefile | 5 ++ samples/bpf/irqlat_kern.c | 81 ++++++++++++++++++++++++++++++ samples/bpf/irqlat_user.c | 100 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 187 insertions(+) create mode 100644 samples/bpf/irqlat_kern.c create mode 100644 samples/bpf/irqlat_user.c diff --git a/samples/bpf/.gitignore b/samples/bpf/.gitignore index 0e7bfdbff80a..2d727f041f51 100644 --- a/samples/bpf/.gitignore +++ b/samples/bpf/.gitignore @@ -61,3 +61,4 @@ iperf.* /vmlinux.h /bpftool/ /libbpf/ +irqlat diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 38638845db9d..df2daab128f0 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -60,6 +60,8 @@ tprogs-y += xdp_redirect_map tprogs-y += xdp_redirect tprogs-y += xdp_monitor +tprogs-y += irqlat + # Libbpf dependencies LIBBPF_SRC = $(TOOLS_PATH)/lib/bpf LIBBPF_OUTPUT = $(abspath $(BPF_SAMPLES_PATH))/libbpf @@ -125,6 +127,8 @@ xdp_redirect_map-objs := xdp_redirect_map_user.o $(XDP_SAMPLE) xdp_redirect-objs := xdp_redirect_user.o $(XDP_SAMPLE) xdp_monitor-objs := xdp_monitor_user.o $(XDP_SAMPLE) +irqlat-objs := irqlat_user.o + # Tell kbuild to always build the programs always-y := $(tprogs-y) always-y += sockex1_kern.o @@ -181,6 +185,7 @@ always-y += ibumad_kern.o always-y += hbm_out_kern.o always-y += hbm_edt_kern.o always-y += xdpsock_kern.o +always-y += irqlat_kern.o ifeq ($(ARCH), arm) # Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux diff --git a/samples/bpf/irqlat_kern.c b/samples/bpf/irqlat_kern.c new file mode 100644 index 000000000000..0037dcda67cf --- /dev/null +++ b/samples/bpf/irqlat_kern.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2022 Kylin + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include +#include +#include +#include + +#define MAX_CPUS 128 + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, u64); + __uint(max_entries, MAX_CPUS); +} irq_ts SEC(".maps"); + +SEC("tracepoint/irq/irq_handler_entry") +int on_irq_entry(struct pt_regs *ctx) +{ + int cpu = bpf_get_smp_processor_id(); + u64 *ts = bpf_map_lookup_elem(&irq_ts, &cpu); + + if (ts) + *ts = bpf_ktime_get_ns(); + + return 0; +} + +struct datares { + u64 entries; + u64 total; + u64 max; + u64 min; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct datares); + __uint(max_entries, MAX_CPUS); +} irq_lat SEC(".maps"); + +SEC("tracepoint/irq/irq_handler_exit") +int on_irq_exit(struct pt_regs *ctx) +{ + u64 *ts, cur_ts, delta, *val; + int cpu; + struct datares *res; + + cpu = bpf_get_smp_processor_id(); + ts = bpf_map_lookup_elem(&irq_ts, &cpu); + if (!ts) + return 0; + + cur_ts = bpf_ktime_get_ns(); + delta = cur_ts - *ts; + + res = bpf_map_lookup_elem(&irq_lat, &cpu); + if (!res) + return 0; + + res->entries++; + res->total += delta; + if (res->max < delta) + res->max = delta; + if (res->min == 0 || res->min > delta) + res->min = delta; + + if (res->total >= U64_MAX) + __builtin_memset(res, 0, sizeof(struct datares)); + + return 0; +} + +char _license[] SEC("license") = "GPL"; diff --git a/samples/bpf/irqlat_user.c b/samples/bpf/irqlat_user.c new file mode 100644 index 000000000000..3a5a43b9fce9 --- /dev/null +++ b/samples/bpf/irqlat_user.c @@ -0,0 +1,100 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2022 Kylin + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace_helpers.h" + +#define MAX_CPUS 128 +static int map_fd[2]; + +struct datares { + __u64 entries; + __u64 total; + __u64 max; + __u64 min; +}; + +static void get_data(int fd) +{ + int i; + struct datares res; + __u64 avg; + + /* Clear screen */ + printf("\033[2J"); + + /* Header */ + printf("\nirq Latency statistics: (ns)\n"); + for (i = 0; i < MAX_CPUS; i++) { + bpf_map_lookup_elem(fd, &i, &res); + + if (res.entries == 0) + continue; + + avg = res.total / res.entries; + printf("cpu:%d, max:%llu, min:%llu, avg:%llu\n", + i, res.max, res.min, avg); + } +} + +int main(int argc, char **argv) +{ + char filename[256]; + struct bpf_object *obj = NULL; + struct bpf_link *links[2]; + struct bpf_program *prog; + int delay = 1, i = 0; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + obj = bpf_object__open_file(filename, NULL); + if (libbpf_get_error(obj)) { + fprintf(stderr, "ERROR: opening BPF object file failed\n"); + obj = NULL; + goto cleanup; + } + + /* load BPF program */ + if (bpf_object__load(obj)) { + fprintf(stderr, "ERROR: loading BPF object file failed\n"); + goto cleanup; + } + + map_fd[0] = bpf_object__find_map_fd_by_name(obj, "irq_ts"); + map_fd[1] = bpf_object__find_map_fd_by_name(obj, "irq_lat"); + if (map_fd[0] < 0 || map_fd[1] < 0) { + fprintf(stderr, "ERROR: finding a map in obj file failed\n"); + goto cleanup; + } + + bpf_object__for_each_program(prog, obj) { + links[i] = bpf_program__attach(prog); + if (libbpf_get_error(links[i])) { + fprintf(stderr, "ERROR: bpf_program__attach failed\n"); + links[i] = NULL; + goto cleanup; + } + i++; + } + + while (1) { + sleep(delay); + get_data(map_fd[1]); + } + +cleanup: + for (i--; i >= 0; i--) + bpf_link__destroy(links[i]); + + bpf_object__close(obj); + return 0; +}