samples/bpf: convert xdp_sample_pkts_user to perf_buffer API

Convert xdp_sample_pkts_user to libbpf's perf_buffer API.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/samples/bpf/xdp_sample_pkts_user.c b/samples/bpf/xdp_sample_pkts_user.c
index dc66345..3002714 100644 (file)
--- a/samples/bpf/xdp_sample_pkts_user.c
+++ b/samples/bpf/xdp_sample_pkts_user.c
@@ -17,14 +17,13 @@
 #include <linux/if_link.h>
 
 #include "perf-sys.h"
-#include "trace_helpers.h"
 
 #define MAX_CPUS 128
-static int pmu_fds[MAX_CPUS], if_idx;
-static struct perf_event_mmap_page *headers[MAX_CPUS];
+static int if_idx;
 static char *if_name;
 static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
 static __u32 prog_id;
+static struct perf_buffer *pb = NULL;
 
 static int do_attach(int idx, int fd, const char *name)
 {
@@ -73,7 +72,7 @@ static int do_detach(int idx, const char *name)
 
 #define SAMPLE_SIZE 64
 
-static int print_bpf_output(void *data, int size)
+static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
 {
        struct {
                __u16 cookie;
@@ -83,45 +82,20 @@ static int print_bpf_output(void *data, int size)
        int i;
 
        if (e->cookie != 0xdead) {
-               printf("BUG cookie %x sized %d\n",
-                      e->cookie, size);
-               return LIBBPF_PERF_EVENT_ERROR;
+               printf("BUG cookie %x sized %d\n", e->cookie, size);
+               return;
        }
 
        printf("Pkt len: %-5d bytes. Ethernet hdr: ", e->pkt_len);
        for (i = 0; i < 14 && i < e->pkt_len; i++)
                printf("%02x ", e->pkt_data[i]);
        printf("\n");
-
-       return LIBBPF_PERF_EVENT_CONT;
-}
-
-static void test_bpf_perf_event(int map_fd, int num)
-{
-       struct perf_event_attr attr = {
-               .sample_type = PERF_SAMPLE_RAW,
-               .type = PERF_TYPE_SOFTWARE,
-               .config = PERF_COUNT_SW_BPF_OUTPUT,
-               .wakeup_events = 1, /* get an fd notification for every event */
-       };
-       int i;
-
-       for (i = 0; i < num; i++) {
-               int key = i;
-
-               pmu_fds[i] = sys_perf_event_open(&attr, -1/*pid*/, i/*cpu*/,
-                                                -1/*group_fd*/, 0);
-
-               assert(pmu_fds[i] >= 0);
-               assert(bpf_map_update_elem(map_fd, &key,
-                                          &pmu_fds[i], BPF_ANY) == 0);
-               ioctl(pmu_fds[i], PERF_EVENT_IOC_ENABLE, 0);
-       }
 }
 
 static void sig_handler(int signo)
 {
        do_detach(if_idx, if_name);
+       perf_buffer__free(pb);
        exit(0);
 }
 
@@ -140,13 +114,13 @@ int main(int argc, char **argv)
        struct bpf_prog_load_attr prog_load_attr = {
                .prog_type      = BPF_PROG_TYPE_XDP,
        };
+       struct perf_buffer_opts pb_opts = {};
        const char *optstr = "F";
        int prog_fd, map_fd, opt;
        struct bpf_object *obj;
        struct bpf_map *map;
        char filename[256];
-       int ret, err, i;
-       int numcpus;
+       int ret, err;
 
        while ((opt = getopt(argc, argv, optstr)) != -1) {
                switch (opt) {
@@ -169,10 +143,6 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       numcpus = get_nprocs();
-       if (numcpus > MAX_CPUS)
-               numcpus = MAX_CPUS;
-
        snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
        prog_load_attr.file = filename;
 
@@ -211,14 +181,17 @@ int main(int argc, char **argv)
                return 1;
        }
 
-       test_bpf_perf_event(map_fd, numcpus);
+       pb_opts.sample_cb = print_bpf_output;
+       pb = perf_buffer__new(map_fd, 8, &pb_opts);
+       err = libbpf_get_error(pb);
+       if (err) {
+               perror("perf_buffer setup failed");
+               return 1;
+       }
 
-       for (i = 0; i < numcpus; i++)
-               if (perf_event_mmap_header(pmu_fds[i], &headers[i]) < 0)
-                       return 1;
+       while ((ret = perf_buffer__poll(pb, 1000)) >= 0) {
+       }
 
-       ret = perf_event_poller_multi(pmu_fds, headers, numcpus,
-                                     print_bpf_output);
        kill(0, SIGINT);
        return ret;
 }