Commit f0c328f8 authored by Daniel T. Lee's avatar Daniel T. Lee Committed by Alexei Starovoitov
Browse files

samples: bpf: Refactor tracepoint tracing programs with libbpf 



For the problem of increasing fragmentation of the bpf loader programs,
instead of using bpf_loader.o, which is used in samples/bpf, this
commit refactors the existing tracepoint tracing programs with libbbpf
bpf loader.

    - Adding a tracepoint event and attaching a bpf program to it was done
    through bpf_program_attach().
    - Instead of using the existing BPF MAP definition, MAP definition
    has been refactored with the new BTF-defined MAP format.

Signed-off-by: default avatarDaniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-4-danieltimlee@gmail.com
parent 3677d0a1

samples/bpf/Makefile

+3 −3
Original line number Diff line number Diff line
@@ -74,7 +74,7 @@ tracex7-objs := tracex7_user.o 
test_probe_write_user-objs := test_probe_write_user_user.o

trace_output-objs := trace_output_user.o $(TRACE_HELPERS)

lathist-objs := lathist_user.o

offwaketime-objs := bpf_load.o offwaketime_user.o $(TRACE_HELPERS)

offwaketime-objs := offwaketime_user.o $(TRACE_HELPERS)

spintest-objs := spintest_user.o $(TRACE_HELPERS)

map_perf_test-objs := map_perf_test_user.o

test_overhead-objs := bpf_load.o test_overhead_user.o
@@ -100,8 +100,8 @@ xdp_redirect_map-objs := xdp_redirect_map_user.o 
xdp_redirect_cpu-objs := bpf_load.o xdp_redirect_cpu_user.o

xdp_monitor-objs := bpf_load.o xdp_monitor_user.o

xdp_rxq_info-objs := xdp_rxq_info_user.o

syscall_tp-objs := bpf_load.o syscall_tp_user.o

cpustat-objs := bpf_load.o cpustat_user.o

syscall_tp-objs := syscall_tp_user.o

cpustat-objs := cpustat_user.o

xdp_adjust_tail-objs := xdp_adjust_tail_user.o

xdpsock-objs := xdpsock_user.o

xdp_fwd-objs := xdp_fwd_user.o

samples/bpf/cpustat_kern.c

+18 −18
Original line number Diff line number Diff line
@@ -51,28 +51,28 @@ static int cpu_opps[] = { 208000, 432000, 729000, 960000, 1200000 }; 
#define MAP_OFF_PSTATE_IDX	3

#define MAP_OFF_NUM		4



struct bpf_map_def SEC("maps") my_map = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(u32),

	.value_size = sizeof(u64),

	.max_entries = MAX_CPU * MAP_OFF_NUM,

};

struct {

	__uint(type, BPF_MAP_TYPE_ARRAY);

	__type(key, u32);

	__type(value, u64);

	__uint(max_entries, MAX_CPU * MAP_OFF_NUM);

} my_map SEC(".maps");



/* cstate_duration records duration time for every idle state per CPU */

struct bpf_map_def SEC("maps") cstate_duration = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(u32),

	.value_size = sizeof(u64),

	.max_entries = MAX_CPU * MAX_CSTATE_ENTRIES,

};

struct {

	__uint(type, BPF_MAP_TYPE_ARRAY);

	__type(key, u32);

	__type(value, u64);

	__uint(max_entries, MAX_CPU * MAX_CSTATE_ENTRIES);

} cstate_duration SEC(".maps");



/* pstate_duration records duration time for every operating point per CPU */

struct bpf_map_def SEC("maps") pstate_duration = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(u32),

	.value_size = sizeof(u64),

	.max_entries = MAX_CPU * MAX_PSTATE_ENTRIES,

};

struct {

	__uint(type, BPF_MAP_TYPE_ARRAY);

	__type(key, u32);

	__type(value, u64);

	__uint(max_entries, MAX_CPU * MAX_PSTATE_ENTRIES);

} pstate_duration SEC(".maps");



/*

 * The trace events for cpu_idle and cpu_frequency are taken from:

samples/bpf/cpustat_user.c

+40 −7
Original line number Diff line number Diff line
@@ -9,7 +9,6 @@ 
#include <string.h>

#include <unistd.h>

#include <fcntl.h>

#include <linux/bpf.h>

#include <locale.h>

#include <sys/types.h>

#include <sys/stat.h>
@@ -18,7 +17,9 @@ 
#include <sys/wait.h>



#include <bpf/bpf.h>

#include "bpf_load.h"

#include <bpf/libbpf.h>



static int cstate_map_fd, pstate_map_fd;



#define MAX_CPU			8

#define MAX_PSTATE_ENTRIES	5
@@ -181,21 +182,50 @@ static void int_exit(int sig) 
{

	cpu_stat_inject_cpu_idle_event();

	cpu_stat_inject_cpu_frequency_event();

	cpu_stat_update(map_fd[1], map_fd[2]);

	cpu_stat_update(cstate_map_fd, pstate_map_fd);

	cpu_stat_print();

	exit(0);

}



int main(int argc, char **argv)

{

	struct bpf_link *link = NULL;

	struct bpf_program *prog;

	struct bpf_object *obj;

	char filename[256];

	int ret;



	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");

		return 0;

	}



	if (load_bpf_file(filename)) {

		printf("%s", bpf_log_buf);

		return 1;

	prog = bpf_object__find_program_by_name(obj, "bpf_prog1");

	if (!prog) {

		printf("finding a prog in obj file failed\n");

		goto cleanup;

	}



	/* load BPF program */

	if (bpf_object__load(obj)) {

		fprintf(stderr, "ERROR: loading BPF object file failed\n");

		goto cleanup;

	}



	cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");

	pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");

	if (cstate_map_fd < 0 || pstate_map_fd < 0) {

		fprintf(stderr, "ERROR: finding a map in obj file failed\n");

		goto cleanup;

	}



	link = bpf_program__attach(prog);

	if (libbpf_get_error(link)) {

		fprintf(stderr, "ERROR: bpf_program__attach failed\n");

		link = NULL;

		goto cleanup;

	}



	ret = cpu_stat_inject_cpu_idle_event();
@@ -210,10 +240,13 @@ int main(int argc, char **argv) 
	signal(SIGTERM, int_exit);



	while (1) {

		cpu_stat_update(map_fd[1], map_fd[2]);

		cpu_stat_update(cstate_map_fd, pstate_map_fd);

		cpu_stat_print();

		sleep(5);

	}



cleanup:

	bpf_link__destroy(link);

	bpf_object__close(obj);

	return 0;

}

samples/bpf/offwaketime_kern.c

+26 −26
Original line number Diff line number Diff line
@@ -28,38 +28,38 @@ struct key_t { 
	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 {

	__uint(type, BPF_MAP_TYPE_HASH);

	__type(key, struct key_t);

	__type(value, u64);

	__uint(max_entries, 10000);

} counts SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__type(key, u32);

	__type(value, u64);

	__uint(max_entries, 10000);

} start SEC(".maps");



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,

};

struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__type(key, u32);

	__type(value, struct wokeby_t);

	__uint(max_entries, 10000);

} wokeby SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_STACK_TRACE);

	__uint(key_size, sizeof(u32));

	__uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64));

	__uint(max_entries, 10000);

} stackmap SEC(".maps");



#define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)

samples/bpf/offwaketime_user.c

+51 −15
Original line number Diff line number Diff line
@@ -5,19 +5,19 @@ 
#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 <bpf/libbpf.h>

#include "bpf_load.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;
@@ -52,14 +52,14 @@ static void print_stack(struct key_t *key, __u64 count) 
	int i;



	printf("%s;", key->target);

	if (bpf_map_lookup_elem(map_fd[3], &key->tret, ip) != 0) {

	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[3], &key->wret, ip) != 0) {

	if (bpf_map_lookup_elem(map_fd[1], &key->wret, ip) != 0) {

		printf("---;");

	} else {

		for (i = 0; i < PERF_MAX_STACK_DEPTH; i++)
@@ -96,23 +96,54 @@ static void int_exit(int sig) 
int main(int argc, char **argv)

{

	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};

	struct bpf_object *obj = NULL;

	struct bpf_link *links[2];

	struct bpf_program *prog;

	int delay = 1, i = 0;

	char filename[256];

	int delay = 1;



	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

	setrlimit(RLIMIT_MEMLOCK, &r);



	signal(SIGINT, int_exit);

	signal(SIGTERM, int_exit);

	if (setrlimit(RLIMIT_MEMLOCK, &r)) {

		perror("setrlimit(RLIMIT_MEMLOCK)");

		return 1;

	}



	if (load_kallsyms()) {

		printf("failed to process /proc/kallsyms\n");

		return 2;

	}



	if (load_bpf_file(filename)) {

		printf("%s", bpf_log_buf);

		return 1;

	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, "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)
@@ -120,5 +151,10 @@ int main(int argc, char **argv) 
	sleep(delay);

	print_stacks(map_fd[0]);



cleanup:

	for (i--; i >= 0; i--)

		bpf_link__destroy(links[i]);



	bpf_object__close(obj);

	return 0;

}