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samples/bpf: move common-purpose trace functions to selftests

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There is no functionality change in this patch. The common-purpose
trace functions, including perf_event polling and ksym lookup,
are moved from trace_output_user.c and bpf_load.c to
selftests/bpf/trace_helpers.c so that these function can
be reused later in selftests.

Acked-by: Alexei Starovoitov <ast@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Yonghong Song
2018-04-28 22:28:13 -07:00
committed by Alexei Starovoitov
parent de2ff05f48
commit 28dbf861de
10 changed files with 223 additions and 175 deletions
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110
samples/bpf/trace_output_user.c
View File

@@ -21,100 +21,10 @@
#include "libbpf.h"
#include "bpf_load.h"
#include "perf-sys.h"
#include "trace_helpers.h"
static int pmu_fd;
int page_size;
int page_cnt = 8;
volatile struct perf_event_mmap_page *header;
typedef void (*print_fn)(void *data, int size);
static int perf_event_mmap(int fd)
{
void *base;
int mmap_size;
page_size = getpagesize();
mmap_size = page_size * (page_cnt + 1);
base = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (base == MAP_FAILED) {
printf("mmap err\n");
return -1;
}
header = base;
return 0;
}
static int perf_event_poll(int fd)
{
struct pollfd pfd = { .fd = fd, .events = POLLIN };
return poll(&pfd, 1, 1000);
}
struct perf_event_sample {
struct perf_event_header header;
__u32 size;
char data[];
};
static void perf_event_read(print_fn fn)
{
__u64 data_tail = header->data_tail;
__u64 data_head = header->data_head;
__u64 buffer_size = page_cnt * page_size;
void *base, *begin, *end;
char buf[256];
asm volatile("" ::: "memory"); /* in real code it should be smp_rmb() */
if (data_head == data_tail)
return;
base = ((char *)header) + page_size;
begin = base + data_tail % buffer_size;
end = base + data_head % buffer_size;
while (begin != end) {
struct perf_event_sample *e;
e = begin;
if (begin + e->header.size > base + buffer_size) {
long len = base + buffer_size - begin;
assert(len < e->header.size);
memcpy(buf, begin, len);
memcpy(buf + len, base, e->header.size - len);
e = (void *) buf;
begin = base + e->header.size - len;
} else if (begin + e->header.size == base + buffer_size) {
begin = base;
} else {
begin += e->header.size;
}
if (e->header.type == PERF_RECORD_SAMPLE) {
fn(e->data, e->size);
} else if (e->header.type == PERF_RECORD_LOST) {
struct {
struct perf_event_header header;
__u64 id;
__u64 lost;
} *lost = (void *) e;
printf("lost %lld events\n", lost->lost);
} else {
printf("unknown event type=%d size=%d\n",
e->header.type, e->header.size);
}
}
__sync_synchronize(); /* smp_mb() */
header->data_tail = data_head;
}
static __u64 time_get_ns(void)
{
struct timespec ts;
@@ -127,7 +37,7 @@ static __u64 start_time;
#define MAX_CNT 100000ll
static void print_bpf_output(void *data, int size)
static int print_bpf_output(void *data, int size)
{
static __u64 cnt;
struct {
@@ -138,7 +48,7 @@ static void print_bpf_output(void *data, int size)
if (e->cookie != 0x12345678) {
printf("BUG pid %llx cookie %llx sized %d\n",
e->pid, e->cookie, size);
kill(0, SIGINT);
return PERF_EVENT_ERROR;
}
cnt++;
@@ -146,8 +56,10 @@ static void print_bpf_output(void *data, int size)
if (cnt == MAX_CNT) {
printf("recv %lld events per sec\n",
MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
kill(0, SIGINT);
return PERF_EVENT_DONE;
}
return PERF_EVENT_CONT;
}
static void test_bpf_perf_event(void)
@@ -170,6 +82,7 @@ int main(int argc, char **argv)
{
char filename[256];
FILE *f;
int ret;
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
@@ -187,10 +100,7 @@ int main(int argc, char **argv)
(void) f;
start_time = time_get_ns();
for (;;) {
perf_event_poll(pmu_fd);
perf_event_read(print_bpf_output);
}
return 0;
ret = perf_event_poller(pmu_fd, print_bpf_output);
kill(0, SIGINT);
return ret;
}