linux-next/samples/bpf/offwaketime_user.c

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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Facebook
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/perf_event.h>
#include <errno.h>
#include <stdbool.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
#include "trace_helpers.h"
#define PRINT_RAW_ADDR 0
/* counts, stackmap */
static int map_fd[2];
static void print_ksym(__u64 addr)
{
struct ksym *sym;
if (!addr)
return;
sym = ksym_search(addr);
if (!sym) {
printf("ksym not found. Is kallsyms loaded?\n");
return;
}
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_map_lookup_elem(map_fd[1], &key->tret, ip) != 0) {
printf("---;");
} else {
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_ksym(ip[i]);
}
printf("-;");
if (bpf_map_lookup_elem(map_fd[1], &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;
samples/bpf: Make samples more libbpf-centric Switch all of the sample code to use the function names from tools/lib/bpf so that they're consistent with that, and to declare their own log buffers. This allow the next commit to be purely devoted to getting rid of the duplicate library in samples/bpf. Committer notes: Testing it: On a fedora rawhide container, with clang/llvm 3.9, sharing the host linux kernel git tree: # make O=/tmp/build/linux/ headers_install # make O=/tmp/build/linux -C samples/bpf/ Since I forgot to make it privileged, just tested it outside the container, using what it generated: # uname -a Linux jouet 4.9.0-rc8+ #1 SMP Mon Dec 12 11:20:49 BRT 2016 x86_64 x86_64 x86_64 GNU/Linux # cd /var/lib/docker/devicemapper/mnt/c43e09a53ff56c86a07baf79847f00e2cc2a17a1e2220e1adbf8cbc62734feda/rootfs/tmp/build/linux/samples/bpf/ # ls -la offwaketime -rwxr-xr-x. 1 root root 24200 Dec 15 12:19 offwaketime # file offwaketime offwaketime: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=c940d3f127d5e66cdd680e42d885cb0b64f8a0e4, not stripped # readelf -SW offwaketime_kern.o | grep PROGBITS [ 2] .text PROGBITS 0000000000000000 000040 000000 00 AX 0 0 4 [ 3] kprobe/try_to_wake_up PROGBITS 0000000000000000 000040 0000d8 00 AX 0 0 8 [ 5] tracepoint/sched/sched_switch PROGBITS 0000000000000000 000118 000318 00 AX 0 0 8 [ 7] maps PROGBITS 0000000000000000 000430 000050 00 WA 0 0 4 [ 8] license PROGBITS 0000000000000000 000480 000004 00 WA 0 0 1 [ 9] version PROGBITS 0000000000000000 000484 000004 00 WA 0 0 4 # ./offwaketime | head -5 swapper/1;start_secondary;cpu_startup_entry;schedule_preempt_disabled;schedule;__schedule;-;---;; 106 CPU 0/KVM;entry_SYSCALL_64_fastpath;sys_ioctl;do_vfs_ioctl;kvm_vcpu_ioctl;kvm_arch_vcpu_ioctl_run;kvm_vcpu_block;schedule;__schedule;-;try_to_wake_up;swake_up_locked;swake_up;apic_timer_expired;apic_timer_fn;__hrtimer_run_queues;hrtimer_interrupt;local_apic_timer_interrupt;smp_apic_timer_interrupt;__irqentry_text_start;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary;;swapper/3 2 Compositor;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;futex_requeue;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;SoftwareVsyncTh 5 firefox;entry_SYSCALL_64_fastpath;sys_poll;do_sys_poll;poll_schedule_timeout;schedule_hrtimeout_range;schedule_hrtimeout_range_clock;schedule;__schedule;-;try_to_wake_up;pollwake;__wake_up_common;__wake_up_sync_key;pipe_write;__vfs_write;vfs_write;sys_write;entry_SYSCALL_64_fastpath;;Timer 13 JS Helper;entry_SYSCALL_64_fastpath;sys_futex;do_futex;futex_wait;futex_wait_queue_me;schedule;__schedule;-;try_to_wake_up;do_futex;sys_futex;entry_SYSCALL_64_fastpath;;firefox 2 # Signed-off-by: Joe Stringer <joe@ovn.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Wang Nan <wangnan0@huawei.com> Cc: netdev@vger.kernel.org Link: http://lkml.kernel.org/r/20161214224342.12858-2-joe@ovn.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-12-14 22:43:38 +00:00
while (bpf_map_get_next_key(fd, &key, &next_key) == 0) {
bpf_map_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 bpf_object *obj = NULL;
struct bpf_link *links[2];
struct bpf_program *prog;
int delay = 1, i = 0;
char filename[256];
if (load_kallsyms()) {
printf("failed to process /proc/kallsyms\n");
return 2;
}
snprintf(filename, sizeof(filename), "%s.bpf.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, "counts");
map_fd[1] = bpf_object__find_map_fd_by_name(obj, "stackmap");
if (map_fd[0] < 0 || map_fd[1] < 0) {
fprintf(stderr, "ERROR: finding a map in obj file failed\n");
goto cleanup;
}
signal(SIGINT, int_exit);
signal(SIGTERM, int_exit);
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++;
}
if (argc > 1)
delay = atoi(argv[1]);
sleep(delay);
print_stacks(map_fd[0]);
cleanup:
for (i--; i >= 0; i--)
bpf_link__destroy(links[i]);
bpf_object__close(obj);
return 0;
}