1 files changed, 115 insertions, 0 deletions
diff --git a/net/activity_stats.c b/net/activity_stats.c
new file mode 100644
index 000000000000..8a3e93470069
--- /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);
+