diff options
Diffstat (limited to 'samples')
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/bpf_helpers.h | 2 | ||||
| -rw-r--r-- | samples/bpf/offwaketime_kern.c | 131 | ||||
| -rw-r--r-- | samples/bpf/offwaketime_user.c | 185 |
4 files changed, 322 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index edd638b5825f..c4f8ae0c8afe 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -16,6 +16,7 @@ hostprogs-y += tracex5 hostprogs-y += tracex6 hostprogs-y += trace_output hostprogs-y += lathist +hostprogs-y += offwaketime test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -32,6 +33,7 @@ tracex5-objs := bpf_load.o libbpf.o tracex5_user.o tracex6-objs := bpf_load.o libbpf.o tracex6_user.o trace_output-objs := bpf_load.o libbpf.o trace_output_user.o lathist-objs := bpf_load.o libbpf.o lathist_user.o +offwaketime-objs := bpf_load.o libbpf.o offwaketime_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -47,6 +49,7 @@ always += tracex6_kern.o always += trace_output_kern.o always += tcbpf1_kern.o always += lathist_kern.o +always += offwaketime_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -63,6 +66,7 @@ HOSTLOADLIBES_tracex5 += -lelf HOSTLOADLIBES_tracex6 += -lelf HOSTLOADLIBES_trace_output += -lelf -lrt HOSTLOADLIBES_lathist += -lelf +HOSTLOADLIBES_offwaketime += -lelf # point this to your LLVM backend with bpf support LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h index 7ad19e1dbaf4..811bcca0f29d 100644 --- a/samples/bpf/bpf_helpers.h +++ b/samples/bpf/bpf_helpers.h @@ -39,6 +39,8 @@ static int (*bpf_redirect)(int ifindex, int flags) = (void *) BPF_FUNC_redirect; static int (*bpf_perf_event_output)(void *ctx, void *map, int index, void *data, int size) = (void *) BPF_FUNC_perf_event_output; +static int (*bpf_get_stackid)(void *ctx, void *map, int flags) = + (void *) BPF_FUNC_get_stackid; /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c new file mode 100644 index 000000000000..c0aa5a9b9c48 --- /dev/null +++ b/samples/bpf/offwaketime_kern.c @@ -0,0 +1,131 @@ +/* Copyright (c) 2016 Facebook + * + * 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 <uapi/linux/bpf.h> +#include "bpf_helpers.h" +#include <uapi/linux/ptrace.h> +#include <uapi/linux/perf_event.h> +#include <linux/version.h> +#include <linux/sched.h> + +#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;}) + +#define MINBLOCK_US 1 + +struct key_t { + char waker[TASK_COMM_LEN]; + char target[TASK_COMM_LEN]; + u32 wret; + u32 tret; +}; + +struct bpf_map_def SEC("maps") counts = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(struct key_t), + .value_size = sizeof(u64), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") start = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(u32), + .value_size = sizeof(u64), + .max_entries = 10000, +}; + +struct wokeby_t { + char name[TASK_COMM_LEN]; + u32 ret; +}; + +struct bpf_map_def SEC("maps") wokeby = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(u32), + .value_size = sizeof(struct wokeby_t), + .max_entries = 10000, +}; + +struct bpf_map_def SEC("maps") stackmap = { + .type = BPF_MAP_TYPE_STACK_TRACE, + .key_size = sizeof(u32), + .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64), + .max_entries = 10000, +}; + +#define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP) + +SEC("kprobe/try_to_wake_up") +int waker(struct pt_regs *ctx) +{ + struct task_struct *p = (void *) PT_REGS_PARM1(ctx); + struct wokeby_t woke = {}; + u32 pid; + + pid = _(p->pid); + + bpf_get_current_comm(&woke.name, sizeof(woke.name)); + woke.ret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS); + + bpf_map_update_elem(&wokeby, &pid, &woke, BPF_ANY); + return 0; +} + +static inline int update_counts(struct pt_regs *ctx, u32 pid, u64 delta) +{ + struct key_t key = {}; + struct wokeby_t *woke; + u64 zero = 0, *val; + + bpf_get_current_comm(&key.target, sizeof(key.target)); + key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS); + + woke = bpf_map_lookup_elem(&wokeby, &pid); + if (woke) { + key.wret = woke->ret; + __builtin_memcpy(&key.waker, woke->name, TASK_COMM_LEN); + bpf_map_delete_elem(&wokeby, &pid); + } + + val = bpf_map_lookup_elem(&counts, &key); + if (!val) { + bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST); + val = bpf_map_lookup_elem(&counts, &key); + if (!val) + return 0; + } + (*val) += delta; + return 0; +} + +SEC("kprobe/finish_task_switch") +int oncpu(struct pt_regs *ctx) +{ + struct task_struct *p = (void *) PT_REGS_PARM1(ctx); + u64 delta, ts, *tsp; + u32 pid; + + /* record previous thread sleep time */ + pid = _(p->pid); + ts = bpf_ktime_get_ns(); + bpf_map_update_elem(&start, &pid, &ts, BPF_ANY); + + /* calculate current thread's delta time */ + pid = bpf_get_current_pid_tgid(); + tsp = bpf_map_lookup_elem(&start, &pid); + if (!tsp) + /* missed start or filtered */ + return 0; + + delta = bpf_ktime_get_ns() - *tsp; + bpf_map_delete_elem(&start, &pid); + delta = delta / 1000; + if (delta < MINBLOCK_US) + return 0; + + return update_counts(ctx, pid, delta); +} +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/offwaketime_user.c b/samples/bpf/offwaketime_user.c new file mode 100644 index 000000000000..17cf3024e22c --- /dev/null +++ b/samples/bpf/offwaketime_user.c @@ -0,0 +1,185 @@ +/* Copyright (c) 2016 Facebook + * + * 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 <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <signal.h> +#include <linux/bpf.h> +#include <string.h> +#include <linux/perf_event.h> +#include <errno.h> +#include <assert.h> +#include <stdbool.h> +#include <sys/resource.h> +#include "libbpf.h" +#include "bpf_load.h" + +#define MAX_SYMS 300000 +#define PRINT_RAW_ADDR 0 + +static struct ksym { + long addr; + char *name; +} syms[MAX_SYMS]; +static int sym_cnt; + +static int ksym_cmp(const void *p1, const void *p2) +{ + return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr; +} + +static int load_kallsyms(void) +{ + FILE *f = fopen("/proc/kallsyms", "r"); + char func[256], buf[256]; + char symbol; + void *addr; + int i = 0; + + if (!f) + return -ENOENT; + + while (!feof(f)) { + if (!fgets(buf, sizeof(buf), f)) + break; + if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3) + break; + if (!addr) + continue; + syms[i].addr = (long) addr; + syms[i].name = strdup(func); + i++; + } + sym_cnt = i; + qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp); + return 0; +} + +static void *search(long key) +{ + int start = 0, end = sym_cnt; + int result; + + while (start < end) { + size_t mid = start + (end - start) / 2; + + result = key - syms[mid].addr; + if (result < 0) + end = mid; + else if (result > 0) + start = mid + 1; + else + return &syms[mid]; + } + + if (start >= 1 && syms[start - 1].addr < key && + key < syms[start].addr) + /* valid ksym */ + return &syms[start - 1]; + + /* out of range. return _stext */ + return &syms[0]; +} + +static void print_ksym(__u64 addr) +{ + struct ksym *sym; + + if (!addr) + return; + sym = search(addr); + if (PRINT_RAW_ADDR) + printf("%s/%llx;", sym->name, addr); + else + printf("%s;", sym->name); +} + +#define TASK_COMM_LEN 16 + +struct key_t { + char waker[TASK_COMM_LEN]; + char target[TASK_COMM_LEN]; + __u32 wret; + __u32 tret; +}; + +static void print_stack(struct key_t *key, __u64 count) +{ + __u64 ip[PERF_MAX_STACK_DEPTH] = {}; + static bool warned; + int i; + + printf("%s;", key->target); + if (bpf_lookup_elem(map_fd[3], &key->tret, ip) != 0) { + printf("---;"); + } else { + for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--) + print_ksym(ip[i]); + } + printf("-;"); + if (bpf_lookup_elem(map_fd[3], &key->wret, ip) != 0) { + printf("---;"); + } else { + for (i = 0; i < PERF_MAX_STACK_DEPTH; i++) + print_ksym(ip[i]); + } + printf(";%s %lld\n", key->waker, count); + + if ((key->tret == -EEXIST || key->wret == -EEXIST) && !warned) { + printf("stackmap collisions seen. Consider increasing size\n"); + warned = true; + } else if (((int)(key->tret) < 0 || (int)(key->wret) < 0)) { + printf("err stackid %d %d\n", key->tret, key->wret); + } +} + +static void print_stacks(int fd) +{ + struct key_t key = {}, next_key; + __u64 value; + + while (bpf_get_next_key(fd, &key, &next_key) == 0) { + bpf_lookup_elem(fd, &next_key, &value); + print_stack(&next_key, value); + key = next_key; + } +} + +static void int_exit(int sig) +{ + print_stacks(map_fd[0]); + exit(0); +} + +int main(int argc, char **argv) +{ + struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY}; + char filename[256]; + int delay = 1; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + setrlimit(RLIMIT_MEMLOCK, &r); + + signal(SIGINT, int_exit); + + if (load_kallsyms()) { + printf("failed to process /proc/kallsyms\n"); + return 2; + } + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + if (argc > 1) + delay = atoi(argv[1]); + sleep(delay); + print_stacks(map_fd[0]); + + return 0; +} |