Commit 1c47910e authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller

samples/bpf: add perf_event+bpf example

The bpf program is called 50 times a second and does hashmap[kern&user_stackid]++
It's primary purpose to check that key bpf helpers like map lookup, update,
get_stackid, trace_printk and ctx access are all working.
It checks:
- PERF_COUNT_HW_CPU_CYCLES on all cpus
- PERF_COUNT_HW_CPU_CYCLES for current process and inherited perf_events to children
- PERF_COUNT_SW_CPU_CLOCK on all cpus
- PERF_COUNT_SW_CPU_CLOCK for current process
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent aa6a5f3c
...@@ -25,6 +25,7 @@ hostprogs-y += test_cgrp2_array_pin ...@@ -25,6 +25,7 @@ hostprogs-y += test_cgrp2_array_pin
hostprogs-y += xdp1 hostprogs-y += xdp1
hostprogs-y += xdp2 hostprogs-y += xdp2
hostprogs-y += test_current_task_under_cgroup hostprogs-y += test_current_task_under_cgroup
hostprogs-y += trace_event
test_verifier-objs := test_verifier.o libbpf.o test_verifier-objs := test_verifier.o libbpf.o
test_maps-objs := test_maps.o libbpf.o test_maps-objs := test_maps.o libbpf.o
...@@ -52,6 +53,7 @@ xdp1-objs := bpf_load.o libbpf.o xdp1_user.o ...@@ -52,6 +53,7 @@ xdp1-objs := bpf_load.o libbpf.o xdp1_user.o
xdp2-objs := bpf_load.o libbpf.o xdp1_user.o xdp2-objs := bpf_load.o libbpf.o xdp1_user.o
test_current_task_under_cgroup-objs := bpf_load.o libbpf.o \ test_current_task_under_cgroup-objs := bpf_load.o libbpf.o \
test_current_task_under_cgroup_user.o test_current_task_under_cgroup_user.o
trace_event-objs := bpf_load.o libbpf.o trace_event_user.o
# Tell kbuild to always build the programs # Tell kbuild to always build the programs
always := $(hostprogs-y) always := $(hostprogs-y)
...@@ -79,6 +81,7 @@ always += test_cgrp2_tc_kern.o ...@@ -79,6 +81,7 @@ always += test_cgrp2_tc_kern.o
always += xdp1_kern.o always += xdp1_kern.o
always += xdp2_kern.o always += xdp2_kern.o
always += test_current_task_under_cgroup_kern.o always += test_current_task_under_cgroup_kern.o
always += trace_event_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(objtree)/usr/include
...@@ -103,6 +106,7 @@ HOSTLOADLIBES_test_overhead += -lelf -lrt ...@@ -103,6 +106,7 @@ HOSTLOADLIBES_test_overhead += -lelf -lrt
HOSTLOADLIBES_xdp1 += -lelf HOSTLOADLIBES_xdp1 += -lelf
HOSTLOADLIBES_xdp2 += -lelf HOSTLOADLIBES_xdp2 += -lelf
HOSTLOADLIBES_test_current_task_under_cgroup += -lelf HOSTLOADLIBES_test_current_task_under_cgroup += -lelf
HOSTLOADLIBES_trace_event += -lelf
# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline: # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
# make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang # make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
......
...@@ -55,6 +55,8 @@ static int (*bpf_skb_get_tunnel_opt)(void *ctx, void *md, int size) = ...@@ -55,6 +55,8 @@ static int (*bpf_skb_get_tunnel_opt)(void *ctx, void *md, int size) =
(void *) BPF_FUNC_skb_get_tunnel_opt; (void *) BPF_FUNC_skb_get_tunnel_opt;
static int (*bpf_skb_set_tunnel_opt)(void *ctx, void *md, int size) = static int (*bpf_skb_set_tunnel_opt)(void *ctx, void *md, int size) =
(void *) BPF_FUNC_skb_set_tunnel_opt; (void *) BPF_FUNC_skb_set_tunnel_opt;
static unsigned long long (*bpf_get_prandom_u32)(void) =
(void *) BPF_FUNC_get_prandom_u32;
/* llvm builtin functions that eBPF C program may use to /* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions * emit BPF_LD_ABS and BPF_LD_IND instructions
......
...@@ -51,6 +51,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) ...@@ -51,6 +51,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0; bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0; bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
bool is_xdp = strncmp(event, "xdp", 3) == 0; bool is_xdp = strncmp(event, "xdp", 3) == 0;
bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
enum bpf_prog_type prog_type; enum bpf_prog_type prog_type;
char buf[256]; char buf[256];
int fd, efd, err, id; int fd, efd, err, id;
...@@ -69,6 +70,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) ...@@ -69,6 +70,8 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
prog_type = BPF_PROG_TYPE_TRACEPOINT; prog_type = BPF_PROG_TYPE_TRACEPOINT;
} else if (is_xdp) { } else if (is_xdp) {
prog_type = BPF_PROG_TYPE_XDP; prog_type = BPF_PROG_TYPE_XDP;
} else if (is_perf_event) {
prog_type = BPF_PROG_TYPE_PERF_EVENT;
} else { } else {
printf("Unknown event '%s'\n", event); printf("Unknown event '%s'\n", event);
return -1; return -1;
...@@ -82,7 +85,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size) ...@@ -82,7 +85,7 @@ static int load_and_attach(const char *event, struct bpf_insn *prog, int size)
prog_fd[prog_cnt++] = fd; prog_fd[prog_cnt++] = fd;
if (is_xdp) if (is_xdp || is_perf_event)
return 0; return 0;
if (is_socket) { if (is_socket) {
...@@ -326,6 +329,7 @@ int load_bpf_file(char *path) ...@@ -326,6 +329,7 @@ int load_bpf_file(char *path)
memcmp(shname_prog, "kretprobe/", 10) == 0 || memcmp(shname_prog, "kretprobe/", 10) == 0 ||
memcmp(shname_prog, "tracepoint/", 11) == 0 || memcmp(shname_prog, "tracepoint/", 11) == 0 ||
memcmp(shname_prog, "xdp", 3) == 0 || memcmp(shname_prog, "xdp", 3) == 0 ||
memcmp(shname_prog, "perf_event", 10) == 0 ||
memcmp(shname_prog, "socket", 6) == 0) memcmp(shname_prog, "socket", 6) == 0)
load_and_attach(shname_prog, insns, data_prog->d_size); load_and_attach(shname_prog, insns, data_prog->d_size);
} }
...@@ -344,6 +348,7 @@ int load_bpf_file(char *path) ...@@ -344,6 +348,7 @@ int load_bpf_file(char *path)
memcmp(shname, "kretprobe/", 10) == 0 || memcmp(shname, "kretprobe/", 10) == 0 ||
memcmp(shname, "tracepoint/", 11) == 0 || memcmp(shname, "tracepoint/", 11) == 0 ||
memcmp(shname, "xdp", 3) == 0 || memcmp(shname, "xdp", 3) == 0 ||
memcmp(shname, "perf_event", 10) == 0 ||
memcmp(shname, "socket", 6) == 0) memcmp(shname, "socket", 6) == 0)
load_and_attach(shname, data->d_buf, data->d_size); load_and_attach(shname, data->d_buf, data->d_size);
} }
......
/* 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 <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include <uapi/linux/bpf_perf_event.h>
#include <uapi/linux/perf_event.h>
#include "bpf_helpers.h"
struct key_t {
char comm[TASK_COMM_LEN];
u32 kernstack;
u32 userstack;
};
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") stackmap = {
.type = BPF_MAP_TYPE_STACK_TRACE,
.key_size = sizeof(u32),
.value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
.max_entries = 10000,
};
#define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
#define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK)
SEC("perf_event")
int bpf_prog1(struct bpf_perf_event_data *ctx)
{
char fmt[] = "CPU-%d period %lld ip %llx";
u32 cpu = bpf_get_smp_processor_id();
struct key_t key;
u64 *val, one = 1;
if (ctx->sample_period < 10000)
/* ignore warmup */
return 0;
bpf_get_current_comm(&key.comm, sizeof(key.comm));
key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS);
key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS);
if ((int)key.kernstack < 0 && (int)key.userstack < 0) {
bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period,
ctx->regs.ip);
return 0;
}
val = bpf_map_lookup_elem(&counts, &key);
if (val)
(*val)++;
else
bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST);
return 0;
}
char _license[] SEC("license") = "GPL";
/* 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 <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <signal.h>
#include <assert.h>
#include <errno.h>
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
#define SAMPLE_FREQ 50
static bool sys_read_seen, sys_write_seen;
static void print_ksym(__u64 addr)
{
struct ksym *sym;
if (!addr)
return;
sym = ksym_search(addr);
printf("%s;", sym->name);
if (!strcmp(sym->name, "sys_read"))
sys_read_seen = true;
else if (!strcmp(sym->name, "sys_write"))
sys_write_seen = true;
}
static void print_addr(__u64 addr)
{
if (!addr)
return;
printf("%llx;", addr);
}
#define TASK_COMM_LEN 16
struct key_t {
char comm[TASK_COMM_LEN];
__u32 kernstack;
__u32 userstack;
};
static void print_stack(struct key_t *key, __u64 count)
{
__u64 ip[PERF_MAX_STACK_DEPTH] = {};
static bool warned;
int i;
printf("%3lld %s;", count, key->comm);
if (bpf_lookup_elem(map_fd[1], &key->kernstack, 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[1], &key->userstack, ip) != 0) {
printf("---;");
} else {
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_addr(ip[i]);
}
printf("\n");
if (key->kernstack == -EEXIST && !warned) {
printf("stackmap collisions seen. Consider increasing size\n");
warned = true;
} else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
printf("err stackid %d %d\n", key->kernstack, key->userstack);
}
}
static void int_exit(int sig)
{
kill(0, SIGKILL);
exit(0);
}
static void print_stacks(void)
{
struct key_t key = {}, next_key;
__u64 value;
__u32 stackid = 0, next_id;
int fd = map_fd[0], stack_map = map_fd[1];
sys_read_seen = sys_write_seen = false;
while (bpf_get_next_key(fd, &key, &next_key) == 0) {
bpf_lookup_elem(fd, &next_key, &value);
print_stack(&next_key, value);
bpf_delete_elem(fd, &next_key);
key = next_key;
}
if (!sys_read_seen || !sys_write_seen) {
printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
int_exit(0);
}
/* clear stack map */
while (bpf_get_next_key(stack_map, &stackid, &next_id) == 0) {
bpf_delete_elem(stack_map, &next_id);
stackid = next_id;
}
}
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int i;
/* open perf_event on all cpus */
for (i = 0; i < nr_cpus; i++) {
pmu_fd[i] = perf_event_open(attr, -1, i, -1, 0);
if (pmu_fd[i] < 0) {
printf("perf_event_open failed\n");
goto all_cpu_err;
}
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
}
system("dd if=/dev/zero of=/dev/null count=5000k");
print_stacks();
all_cpu_err:
for (i--; i >= 0; i--)
close(pmu_fd[i]);
free(pmu_fd);
}
static void test_perf_event_task(struct perf_event_attr *attr)
{
int pmu_fd;
/* open task bound event */
pmu_fd = perf_event_open(attr, 0, -1, -1, 0);
if (pmu_fd < 0) {
printf("perf_event_open failed\n");
return;
}
assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
system("dd if=/dev/zero of=/dev/null count=5000k");
print_stacks();
close(pmu_fd);
}
static void test_bpf_perf_event(void)
{
struct perf_event_attr attr_type_hw = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
.inherit = 1,
};
struct perf_event_attr attr_type_sw = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
.inherit = 1,
};
test_perf_event_all_cpu(&attr_type_hw);
test_perf_event_task(&attr_type_hw);
test_perf_event_all_cpu(&attr_type_sw);
test_perf_event_task(&attr_type_sw);
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
char filename[256];
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 1;
}
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 2;
}
if (fork() == 0) {
read_trace_pipe();
return 0;
}
test_bpf_perf_event();
int_exit(0);
return 0;
}
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