diff options
Diffstat (limited to '')
| -rw-r--r-- | tools/bpf/runqslower/.gitignore | 2 | ||||
| -rw-r--r-- | tools/bpf/runqslower/Makefile | 85 | ||||
| -rw-r--r-- | tools/bpf/runqslower/runqslower.bpf.c | 98 | ||||
| -rw-r--r-- | tools/bpf/runqslower/runqslower.c | 187 | ||||
| -rw-r--r-- | tools/bpf/runqslower/runqslower.h | 13 |
5 files changed, 385 insertions, 0 deletions
diff --git a/tools/bpf/runqslower/.gitignore b/tools/bpf/runqslower/.gitignore new file mode 100644 index 000000000..ffdb70230 --- /dev/null +++ b/tools/bpf/runqslower/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +/.output diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile new file mode 100644 index 000000000..fb1337d69 --- /dev/null +++ b/tools/bpf/runqslower/Makefile @@ -0,0 +1,85 @@ +# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +OUTPUT := .output +CLANG ?= clang +LLC ?= llc +LLVM_STRIP ?= llvm-strip +DEFAULT_BPFTOOL := $(OUTPUT)/sbin/bpftool +BPFTOOL ?= $(DEFAULT_BPFTOOL) +LIBBPF_SRC := $(abspath ../../lib/bpf) +BPFOBJ := $(OUTPUT)/libbpf.a +BPF_INCLUDE := $(OUTPUT) +INCLUDES := -I$(OUTPUT) -I$(BPF_INCLUDE) -I$(abspath ../../lib) \ + -I$(abspath ../../include/uapi) +CFLAGS := -g -Wall + +# Try to detect best kernel BTF source +KERNEL_REL := $(shell uname -r) +VMLINUX_BTF_PATHS := /sys/kernel/btf/vmlinux /boot/vmlinux-$(KERNEL_REL) +VMLINUX_BTF_PATH := $(or $(VMLINUX_BTF),$(firstword \ + $(wildcard $(VMLINUX_BTF_PATHS)))) + +abs_out := $(abspath $(OUTPUT)) +ifeq ($(V),1) +Q = +msg = +else +Q = @ +msg = @printf ' %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))"; +MAKEFLAGS += --no-print-directory +submake_extras := feature_display=0 +endif + +.DELETE_ON_ERROR: + +.PHONY: all clean runqslower +all: runqslower + +runqslower: $(OUTPUT)/runqslower + +clean: + $(call msg,CLEAN) + $(Q)rm -rf $(OUTPUT) runqslower + +$(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(BPFOBJ) + $(call msg,BINARY,$@) + $(Q)$(CC) $(CFLAGS) $^ -lelf -lz -o $@ + +$(OUTPUT)/runqslower.o: runqslower.h $(OUTPUT)/runqslower.skel.h \ + $(OUTPUT)/runqslower.bpf.o + +$(OUTPUT)/runqslower.bpf.o: $(OUTPUT)/vmlinux.h runqslower.h + +$(OUTPUT)/%.skel.h: $(OUTPUT)/%.bpf.o | $(BPFTOOL) + $(call msg,GEN-SKEL,$@) + $(Q)$(BPFTOOL) gen skeleton $< > $@ + +$(OUTPUT)/%.bpf.o: %.bpf.c $(BPFOBJ) | $(OUTPUT) + $(call msg,BPF,$@) + $(Q)$(CLANG) -g -O2 -target bpf $(INCLUDES) \ + -c $(filter %.c,$^) -o $@ && \ + $(LLVM_STRIP) -g $@ + +$(OUTPUT)/%.o: %.c | $(OUTPUT) + $(call msg,CC,$@) + $(Q)$(CC) $(CFLAGS) $(INCLUDES) -c $(filter %.c,$^) -o $@ + +$(OUTPUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $(OUTPUT) + +$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF_PATH) | $(OUTPUT) $(BPFTOOL) + $(call msg,GEN,$@) + $(Q)if [ ! -e "$(VMLINUX_BTF_PATH)" ] ; then \ + echo "Couldn't find kernel BTF; set VMLINUX_BTF to" \ + "specify its location." >&2; \ + exit 1;\ + fi + $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@ + +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(OUTPUT) + $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) \ + OUTPUT=$(abspath $(dir $@))/ $(abspath $@) + +$(DEFAULT_BPFTOOL): + $(Q)$(MAKE) $(submake_extras) -C ../bpftool \ + prefix= OUTPUT=$(abs_out)/ DESTDIR=$(abs_out) install diff --git a/tools/bpf/runqslower/runqslower.bpf.c b/tools/bpf/runqslower/runqslower.bpf.c new file mode 100644 index 000000000..1f18a409f --- /dev/null +++ b/tools/bpf/runqslower/runqslower.bpf.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook +#include "vmlinux.h" +#include <bpf/bpf_helpers.h> +#include "runqslower.h" + +#define TASK_RUNNING 0 +#define BPF_F_CURRENT_CPU 0xffffffffULL + +const volatile __u64 min_us = 0; +const volatile pid_t targ_pid = 0; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __uint(max_entries, 10240); + __type(key, u32); + __type(value, u64); +} start SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(key_size, sizeof(u32)); + __uint(value_size, sizeof(u32)); +} events SEC(".maps"); + +/* record enqueue timestamp */ +__always_inline +static int trace_enqueue(u32 tgid, u32 pid) +{ + u64 ts; + + if (!pid || (targ_pid && targ_pid != pid)) + return 0; + + ts = bpf_ktime_get_ns(); + bpf_map_update_elem(&start, &pid, &ts, 0); + return 0; +} + +SEC("tp_btf/sched_wakeup") +int handle__sched_wakeup(u64 *ctx) +{ + /* TP_PROTO(struct task_struct *p) */ + struct task_struct *p = (void *)ctx[0]; + + return trace_enqueue(p->tgid, p->pid); +} + +SEC("tp_btf/sched_wakeup_new") +int handle__sched_wakeup_new(u64 *ctx) +{ + /* TP_PROTO(struct task_struct *p) */ + struct task_struct *p = (void *)ctx[0]; + + return trace_enqueue(p->tgid, p->pid); +} + +SEC("tp_btf/sched_switch") +int handle__sched_switch(u64 *ctx) +{ + /* TP_PROTO(bool preempt, struct task_struct *prev, + * struct task_struct *next) + */ + struct task_struct *prev = (struct task_struct *)ctx[1]; + struct task_struct *next = (struct task_struct *)ctx[2]; + struct event event = {}; + u64 *tsp, delta_us; + long state; + u32 pid; + + /* ivcsw: treat like an enqueue event and store timestamp */ + if (prev->state == TASK_RUNNING) + trace_enqueue(prev->tgid, prev->pid); + + pid = next->pid; + + /* fetch timestamp and calculate delta */ + tsp = bpf_map_lookup_elem(&start, &pid); + if (!tsp) + return 0; /* missed enqueue */ + + delta_us = (bpf_ktime_get_ns() - *tsp) / 1000; + if (min_us && delta_us <= min_us) + return 0; + + event.pid = pid; + event.delta_us = delta_us; + bpf_get_current_comm(&event.task, sizeof(event.task)); + + /* output */ + bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, + &event, sizeof(event)); + + bpf_map_delete_elem(&start, &pid); + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/bpf/runqslower/runqslower.c b/tools/bpf/runqslower/runqslower.c new file mode 100644 index 000000000..d89715844 --- /dev/null +++ b/tools/bpf/runqslower/runqslower.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) +// Copyright (c) 2019 Facebook +#include <argp.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/resource.h> +#include <time.h> +#include <bpf/libbpf.h> +#include <bpf/bpf.h> +#include "runqslower.h" +#include "runqslower.skel.h" + +struct env { + pid_t pid; + __u64 min_us; + bool verbose; +} env = { + .min_us = 10000, +}; + +const char *argp_program_version = "runqslower 0.1"; +const char *argp_program_bug_address = "<bpf@vger.kernel.org>"; +const char argp_program_doc[] = +"runqslower Trace long process scheduling delays.\n" +" For Linux, uses eBPF, BPF CO-RE, libbpf, BTF.\n" +"\n" +"This script traces high scheduling delays between tasks being\n" +"ready to run and them running on CPU after that.\n" +"\n" +"USAGE: runqslower [-p PID] [min_us]\n" +"\n" +"EXAMPLES:\n" +" runqslower # trace run queue latency higher than 10000 us (default)\n" +" runqslower 1000 # trace run queue latency higher than 1000 us\n" +" runqslower -p 123 # trace pid 123 only\n"; + +static const struct argp_option opts[] = { + { "pid", 'p', "PID", 0, "Process PID to trace"}, + { "verbose", 'v', NULL, 0, "Verbose debug output" }, + {}, +}; + +static error_t parse_arg(int key, char *arg, struct argp_state *state) +{ + static int pos_args; + int pid; + long long min_us; + + switch (key) { + case 'v': + env.verbose = true; + break; + case 'p': + errno = 0; + pid = strtol(arg, NULL, 10); + if (errno || pid <= 0) { + fprintf(stderr, "Invalid PID: %s\n", arg); + argp_usage(state); + } + env.pid = pid; + break; + case ARGP_KEY_ARG: + if (pos_args++) { + fprintf(stderr, + "Unrecognized positional argument: %s\n", arg); + argp_usage(state); + } + errno = 0; + min_us = strtoll(arg, NULL, 10); + if (errno || min_us <= 0) { + fprintf(stderr, "Invalid delay (in us): %s\n", arg); + argp_usage(state); + } + env.min_us = min_us; + break; + default: + return ARGP_ERR_UNKNOWN; + } + return 0; +} + +int libbpf_print_fn(enum libbpf_print_level level, + const char *format, va_list args) +{ + if (level == LIBBPF_DEBUG && !env.verbose) + return 0; + return vfprintf(stderr, format, args); +} + +static int bump_memlock_rlimit(void) +{ + struct rlimit rlim_new = { + .rlim_cur = RLIM_INFINITY, + .rlim_max = RLIM_INFINITY, + }; + + return setrlimit(RLIMIT_MEMLOCK, &rlim_new); +} + +void handle_event(void *ctx, int cpu, void *data, __u32 data_sz) +{ + const struct event *e = data; + struct tm *tm; + char ts[32]; + time_t t; + + time(&t); + tm = localtime(&t); + strftime(ts, sizeof(ts), "%H:%M:%S", tm); + printf("%-8s %-16s %-6d %14llu\n", ts, e->task, e->pid, e->delta_us); +} + +void handle_lost_events(void *ctx, int cpu, __u64 lost_cnt) +{ + printf("Lost %llu events on CPU #%d!\n", lost_cnt, cpu); +} + +int main(int argc, char **argv) +{ + static const struct argp argp = { + .options = opts, + .parser = parse_arg, + .doc = argp_program_doc, + }; + struct perf_buffer_opts pb_opts; + struct perf_buffer *pb = NULL; + struct runqslower_bpf *obj; + int err; + + err = argp_parse(&argp, argc, argv, 0, NULL, NULL); + if (err) + return err; + + libbpf_set_print(libbpf_print_fn); + + err = bump_memlock_rlimit(); + if (err) { + fprintf(stderr, "failed to increase rlimit: %d", err); + return 1; + } + + obj = runqslower_bpf__open(); + if (!obj) { + fprintf(stderr, "failed to open and/or load BPF object\n"); + return 1; + } + + /* initialize global data (filtering options) */ + obj->rodata->targ_pid = env.pid; + obj->rodata->min_us = env.min_us; + + err = runqslower_bpf__load(obj); + if (err) { + fprintf(stderr, "failed to load BPF object: %d\n", err); + goto cleanup; + } + + err = runqslower_bpf__attach(obj); + if (err) { + fprintf(stderr, "failed to attach BPF programs\n"); + goto cleanup; + } + + printf("Tracing run queue latency higher than %llu us\n", env.min_us); + printf("%-8s %-16s %-6s %14s\n", "TIME", "COMM", "PID", "LAT(us)"); + + pb_opts.sample_cb = handle_event; + pb_opts.lost_cb = handle_lost_events; + pb = perf_buffer__new(bpf_map__fd(obj->maps.events), 64, &pb_opts); + err = libbpf_get_error(pb); + if (err) { + pb = NULL; + fprintf(stderr, "failed to open perf buffer: %d\n", err); + goto cleanup; + } + + while ((err = perf_buffer__poll(pb, 100)) >= 0) + ; + printf("Error polling perf buffer: %d\n", err); + +cleanup: + perf_buffer__free(pb); + runqslower_bpf__destroy(obj); + + return err != 0; +} diff --git a/tools/bpf/runqslower/runqslower.h b/tools/bpf/runqslower/runqslower.h new file mode 100644 index 000000000..9db225425 --- /dev/null +++ b/tools/bpf/runqslower/runqslower.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ +#ifndef __RUNQSLOWER_H +#define __RUNQSLOWER_H + +#define TASK_COMM_LEN 16 + +struct event { + char task[TASK_COMM_LEN]; + __u64 delta_us; + pid_t pid; +}; + +#endif /* __RUNQSLOWER_H */ |