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-rw-r--r--samples/bpf/lwt_len_hist_user.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/samples/bpf/lwt_len_hist_user.c b/samples/bpf/lwt_len_hist_user.c
new file mode 100644
index 000000000000..05d783fc5daf
--- /dev/null
+++ b/samples/bpf/lwt_len_hist_user.c
@@ -0,0 +1,76 @@
+#include <linux/unistd.h>
+#include <linux/bpf.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <arpa/inet.h>
+
+#include "libbpf.h"
+#include "bpf_util.h"
+
+#define MAX_INDEX 64
+#define MAX_STARS 38
+
+static void stars(char *str, long val, long max, int width)
+{
+ int i;
+
+ for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)
+ str[i] = '*';
+ if (val > max)
+ str[i - 1] = '+';
+ str[i] = '\0';
+}
+
+int main(int argc, char **argv)
+{
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ const char *map_filename = "/sys/fs/bpf/tc/globals/lwt_len_hist_map";
+ uint64_t values[nr_cpus], sum, max_value = 0, data[MAX_INDEX] = {};
+ uint64_t key = 0, next_key, max_key = 0;
+ char starstr[MAX_STARS];
+ int i, map_fd;
+
+ map_fd = bpf_obj_get(map_filename);
+ if (map_fd < 0) {
+ fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",
+ map_filename, strerror(errno), errno);
+ return -1;
+ }
+
+ while (bpf_get_next_key(map_fd, &key, &next_key) == 0) {
+ if (next_key >= MAX_INDEX) {
+ fprintf(stderr, "Key %lu out of bounds\n", next_key);
+ continue;
+ }
+
+ bpf_lookup_elem(map_fd, &next_key, values);
+
+ sum = 0;
+ for (i = 0; i < nr_cpus; i++)
+ sum += values[i];
+
+ data[next_key] = sum;
+ if (sum && next_key > max_key)
+ max_key = next_key;
+
+ if (sum > max_value)
+ max_value = sum;
+
+ key = next_key;
+ }
+
+ for (i = 1; i <= max_key + 1; i++) {
+ stars(starstr, data[i - 1], max_value, MAX_STARS);
+ printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
+ (1l << i) >> 1, (1l << i) - 1, data[i - 1],
+ MAX_STARS, starstr);
+ }
+
+ close(map_fd);
+
+ return 0;
+}