Commit 47efb302 authored by Kaixu Xia's avatar Kaixu Xia Committed by David S. Miller

samples/bpf: example of get selected PMU counter value

This is a simple example and shows how to use the new ability
to get the selected Hardware PMU counter value.
Signed-off-by: default avatarKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 35578d79
......@@ -12,6 +12,7 @@ hostprogs-y += tracex2
hostprogs-y += tracex3
hostprogs-y += tracex4
hostprogs-y += tracex5
hostprogs-y += tracex6
hostprogs-y += lathist
test_verifier-objs := test_verifier.o libbpf.o
......@@ -25,6 +26,7 @@ tracex2-objs := bpf_load.o libbpf.o tracex2_user.o
tracex3-objs := bpf_load.o libbpf.o tracex3_user.o
tracex4-objs := bpf_load.o libbpf.o tracex4_user.o
tracex5-objs := bpf_load.o libbpf.o tracex5_user.o
tracex6-objs := bpf_load.o libbpf.o tracex6_user.o
lathist-objs := bpf_load.o libbpf.o lathist_user.o
# Tell kbuild to always build the programs
......@@ -37,6 +39,7 @@ always += tracex2_kern.o
always += tracex3_kern.o
always += tracex4_kern.o
always += tracex5_kern.o
always += tracex6_kern.o
always += tcbpf1_kern.o
always += lathist_kern.o
......@@ -51,6 +54,7 @@ HOSTLOADLIBES_tracex2 += -lelf
HOSTLOADLIBES_tracex3 += -lelf
HOSTLOADLIBES_tracex4 += -lelf -lrt
HOSTLOADLIBES_tracex5 += -lelf
HOSTLOADLIBES_tracex6 += -lelf
HOSTLOADLIBES_lathist += -lelf
# point this to your LLVM backend with bpf support
......
......@@ -31,6 +31,8 @@ static unsigned long long (*bpf_get_current_uid_gid)(void) =
(void *) BPF_FUNC_get_current_uid_gid;
static int (*bpf_get_current_comm)(void *buf, int buf_size) =
(void *) BPF_FUNC_get_current_comm;
static int (*bpf_perf_event_read)(void *map, int index) =
(void *) BPF_FUNC_perf_event_read;
/* llvm builtin functions that eBPF C program may use to
* emit BPF_LD_ABS and BPF_LD_IND instructions
......
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") my_map = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = 32,
};
SEC("kprobe/sys_write")
int bpf_prog1(struct pt_regs *ctx)
{
u64 count;
u32 key = bpf_get_smp_processor_id();
char fmt[] = "CPU-%d %llu\n";
count = bpf_perf_event_read(&my_map, key);
bpf_trace_printk(fmt, sizeof(fmt), key, count);
return 0;
}
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;
#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 "libbpf.h"
#include "bpf_load.h"
#define SAMPLE_PERIOD 0x7fffffffffffffffULL
static void test_bpf_perf_event(void)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
int *pmu_fd = malloc(nr_cpus * sizeof(int));
unsigned long value;
int i;
struct perf_event_attr attr_insn_pmu = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_HARDWARE,
.read_format = 0,
.sample_type = 0,
.config = 0,/* PMU: cycles */
};
for (i = 0; i < nr_cpus; i++) {
pmu_fd[i] = perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0);
if (pmu_fd[i] < 0)
printf("event syscall failed\n");
bpf_update_elem(map_fd[0], &i, &pmu_fd[i], BPF_ANY);
ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0);
}
system("ls");
system("pwd");
system("sleep 2");
for (i = 0; i < nr_cpus; i++)
close(pmu_fd[i]);
close(map_fd);
free(pmu_fd);
}
int main(int argc, char **argv)
{
char filename[256];
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
test_bpf_perf_event();
return 0;
}
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