These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / samples / bpf / lathist_user.c

diff --git a/kernel/samples/bpf/lathist_user.c b/kernel/samples/bpf/lathist_user.c
new file mode 100644 (file)
index 0000000..65da8c1
--- /dev/null
+++ b/kernel/samples/bpf/lathist_user.c
@@ -0,0 +1,103 @@
+/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2015 BMW Car IT GmbH
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <linux/bpf.h>
+#include "libbpf.h"
+#include "bpf_load.h"
+
+#define MAX_ENTRIES    20
+#define MAX_CPU                4
+#define MAX_STARS      40
+
+struct cpu_hist {
+       long data[MAX_ENTRIES];
+       long max;
+};
+
+static struct cpu_hist cpu_hist[MAX_CPU];
+
+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';
+}
+
+static void print_hist(void)
+{
+       char starstr[MAX_STARS];
+       struct cpu_hist *hist;
+       int i, j;
+
+       /* clear screen */
+       printf("\033[2J");
+
+       for (j = 0; j < MAX_CPU; j++) {
+               hist = &cpu_hist[j];
+
+               /* ignore CPUs without data (maybe offline?) */
+               if (hist->max == 0)
+                       continue;
+
+               printf("CPU %d\n", j);
+               printf("      latency        : count     distribution\n");
+               for (i = 1; i <= MAX_ENTRIES; i++) {
+                       stars(starstr, hist->data[i - 1], hist->max, MAX_STARS);
+                       printf("%8ld -> %-8ld : %-8ld |%-*s|\n",
+                               (1l << i) >> 1, (1l << i) - 1,
+                               hist->data[i - 1], MAX_STARS, starstr);
+               }
+       }
+}
+
+static void get_data(int fd)
+{
+       long key, value;
+       int c, i;
+
+       for (i = 0; i < MAX_CPU; i++)
+               cpu_hist[i].max = 0;
+
+       for (c = 0; c < MAX_CPU; c++) {
+               for (i = 0; i < MAX_ENTRIES; i++) {
+                       key = c * MAX_ENTRIES + i;
+                       bpf_lookup_elem(fd, &key, &value);
+
+                       cpu_hist[c].data[i] = value;
+                       if (value > cpu_hist[c].max)
+                               cpu_hist[c].max = value;
+               }
+       }
+}
+
+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;
+       }
+
+       while (1) {
+               get_data(map_fd[1]);
+               print_hist();
+               sleep(5);
+       }
+
+       return 0;
+}