1 files changed, 115 insertions, 0 deletions

diff --git a/net/activity_stats.c b/net/activity_stats.c
new file mode 100644
index 00000000000..8a3e9347006
--- /dev/null
+++ b/net/activity_stats.c
@@ -0,0 +1,115 @@
+/* net/activity_stats.c
+ *
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Author: Mike Chan (mike@android.com)
+ */
+
+#include <linux/proc_fs.h>
+#include <linux/suspend.h>
+#include <net/net_namespace.h>
+
+/*
+ * Track transmission rates in buckets (power of 2).
+ * 1,2,4,8...512 seconds.
+ *
+ * Buckets represent the count of network transmissions at least
+ * N seconds apart, where N is 1 << bucket index.
+ */
+#define BUCKET_MAX 10
+
+/* Track network activity frequency */
+static unsigned long activity_stats[BUCKET_MAX];
+static ktime_t last_transmit;
+static ktime_t suspend_time;
+static DEFINE_SPINLOCK(activity_lock);
+
+void activity_stats_update(void)
+{
+        int i;
+        unsigned long flags;
+        ktime_t now;
+        s64 delta;
+
+        spin_lock_irqsave(&activity_lock, flags);
+        now = ktime_get();
+        delta = ktime_to_ns(ktime_sub(now, last_transmit));
+
+        for (i = BUCKET_MAX - 1; i >= 0; i--) {
+                /*
+                 * Check if the time delta between network activity is within the
+                 * minimum bucket range.
+                 */
+                if (delta < (1000000000ULL << i))
+                        continue;
+
+                activity_stats[i]++;
+                last_transmit = now;
+                break;
+        }
+        spin_unlock_irqrestore(&activity_lock, flags);
+}
+
+static int activity_stats_read_proc(char *page, char **start, off_t off,
+                                        int count, int *eof, void *data)
+{
+        int i;
+        int len;
+        char *p = page;
+
+        /* Only print if offset is 0, or we have enough buffer space */
+        if (off || count < (30 * BUCKET_MAX + 22))
+                return -ENOMEM;
+
+        len = snprintf(p, count, "Min Bucket(sec) Count\n");
+        count -= len;
+        p += len;
+
+        for (i = 0; i < BUCKET_MAX; i++) {
+                len = snprintf(p, count, "%15d %lu\n", 1 << i, activity_stats[i]);
+                count -= len;
+                p += len;
+        }
+        *eof = 1;
+
+        return p - page;
+}
+
+static int activity_stats_notifier(struct notifier_block *nb,
+                                        unsigned long event, void *dummy)
+{
+        switch (event) {
+                case PM_SUSPEND_PREPARE:
+                        suspend_time = ktime_get_real();
+                        break;
+
+                case PM_POST_SUSPEND:
+                        suspend_time = ktime_sub(ktime_get_real(), suspend_time);
+                        last_transmit = ktime_sub(last_transmit, suspend_time);
+        }
+
+        return 0;
+}
+
+static struct notifier_block activity_stats_notifier_block = {
+        .notifier_call = activity_stats_notifier,
+};
+
+static int  __init activity_stats_init(void)
+{
+        create_proc_read_entry("activity", S_IRUGO,
+                        init_net.proc_net_stat, activity_stats_read_proc, NULL);
+        return register_pm_notifier(&activity_stats_notifier_block);
+}
+
+subsys_initcall(activity_stats_init);
+