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samples: bpf: Refactor tracepoint tracing programs with libbpf

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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: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200823085334.9413-4-danieltimlee@gmail.com
This commit is contained in:
Daniel T. Lee
2020-08-23 17:53:34 +09:00
committed by Alexei Starovoitov
parent 3677d0a131
commit f0c328f8af
7 changed files with 190 additions and 91 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
samples/bpf/cpustat_user.c
View File

@@ -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;
}