diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 6f4678d..f359619 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -216,6 +216,9 @@ static int ceph_sync_readpages(struct ceph_fs_client *fsc,
 	if (!rc)
 		rc = ceph_osdc_wait_request(osdc, req);
 
+	ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_stamp,
+				 req->r_end_stamp, rc);
+
 	ceph_osdc_put_request(req);
 	dout("readpages result %d\n", rc);
 	return rc;
@@ -299,6 +302,7 @@ static int ceph_readpage(struct file *filp, struct page *page)
 static void finish_read(struct ceph_osd_request *req)
 {
 	struct inode *inode = req->r_inode;
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
 	struct ceph_osd_data *osd_data;
 	int rc = req->r_result <= 0 ? req->r_result : 0;
 	int bytes = req->r_result >= 0 ? req->r_result : 0;
@@ -336,6 +340,10 @@ static void finish_read(struct ceph_osd_request *req)
 		put_page(page);
 		bytes -= PAGE_SIZE;
 	}
+
+	ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_stamp,
+				 req->r_end_stamp, rc);
+
 	kfree(osd_data->pages);
 }
 
@@ -643,6 +651,9 @@ static int ceph_sync_writepages(struct ceph_fs_client *fsc,
 	if (!rc)
 		rc = ceph_osdc_wait_request(osdc, req);
 
+	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_stamp,
+				  req->r_end_stamp, rc);
+
 	ceph_osdc_put_request(req);
 	if (rc == 0)
 		rc = len;
@@ -794,6 +805,9 @@ static void writepages_finish(struct ceph_osd_request *req)
 		ceph_clear_error_write(ci);
 	}
 
+	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_stamp,
+				  req->r_end_stamp, rc);
+
 	/*
 	 * We lost the cache cap, need to truncate the page before
 	 * it is unlocked, otherwise we'd truncate it later in the
@@ -1852,6 +1866,10 @@ int ceph_uninline_data(struct file *filp, struct page *locked_page)
 	err = ceph_osdc_start_request(&fsc->client->osdc, req, false);
 	if (!err)
 		err = ceph_osdc_wait_request(&fsc->client->osdc, req);
+
+	ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_stamp,
+				  req->r_end_stamp, err);
+
 out_put:
 	ceph_osdc_put_request(req);
 	if (err == -ECANCELED)
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index 66b9622..e50499c 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -7,6 +7,7 @@
 #include <linux/ctype.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
+#include <linux/math64.h>
 
 #include <linux/ceph/libceph.h>
 #include <linux/ceph/mon_client.h>
@@ -124,13 +125,71 @@ static int mdsc_show(struct seq_file *s, void *p)
 	return 0;
 }
 
+static s64 get_avg(atomic64_t *totalp, atomic64_t *sump, spinlock_t *lockp,
+		   s64 *total)
+{
+	s64 t, sum, avg = 0;
+
+	spin_lock(lockp);
+	t = atomic64_read(totalp);
+	sum = atomic64_read(sump);
+	spin_unlock(lockp);
+
+	if (likely(t))
+		avg = DIV64_U64_ROUND_CLOSEST(sum, t);
+
+	*total = t;
+	return avg;
+}
+
+#define CEPH_METRIC_SHOW(name, total, avg, min, max, sq) {		\
+	s64 _total, _avg, _min, _max, _sq, _st, _re = 0;		\
+	_avg = jiffies_to_usecs(avg);					\
+	_min = jiffies_to_usecs(min == S64_MAX ? 0 : min);		\
+	_max = jiffies_to_usecs(max);					\
+	_total = total - 1;						\
+	_sq = _total > 0 ? DIV64_U64_ROUND_CLOSEST(sq, _total) : 0;	\
+	_sq = jiffies_to_usecs(_sq);					\
+	_st = int_sqrt64(_sq);						\
+	if (_st > 0) {							\
+		_re = 5 * (_sq - (_st * _st));				\
+		_re = _re > 0 ? _re - 1 : 0;				\
+		_re = _st > 0 ? div64_s64(_re, _st) : 0;		\
+	}								\
+	seq_printf(s, "%-14s%-12lld%-16lld%-16lld%-16lld%lld.%lld\n",	\
+		   name, total, _avg, _min, _max, _st, _re);		\
+}
+
 static int metric_show(struct seq_file *s, void *p)
 {
 	struct ceph_fs_client *fsc = s->private;
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 	struct ceph_client_metric *m = &mdsc->metric;
 	int i, nr_caps = 0;
-
+	s64 total, avg, min, max, sq;
+
+	seq_printf(s, "item          total       avg_lat(us)     min_lat(us)     max_lat(us)     stdev(us)\n");
+	seq_printf(s, "-----------------------------------------------------------------------------------\n");
+
+	avg = get_avg(&m->total_reads,
+		      &m->read_latency_sum,
+		      &m->read_latency_lock,
+		      &total);
+	min = atomic64_read(&m->read_latency_min);
+	max = atomic64_read(&m->read_latency_max);
+	sq = percpu_counter_sum(&m->read_latency_sq_sum);
+	CEPH_METRIC_SHOW("read", total, avg, min, max, sq);
+
+	avg = get_avg(&m->total_writes,
+		      &m->write_latency_sum,
+		      &m->write_latency_lock,
+		      &total);
+	min = atomic64_read(&m->write_latency_min);
+	max = atomic64_read(&m->write_latency_max);
+	sq = percpu_counter_sum(&m->write_latency_sq_sum);
+	CEPH_METRIC_SHOW("write", total, avg, min, max, sq);
+
+	seq_printf(s, "\n");
 	seq_printf(s, "item          total           miss            hit\n");
 	seq_printf(s, "-------------------------------------------------\n");
 
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 4a5ccbb..8e40022 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -906,6 +906,10 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
 		ret = ceph_osdc_start_request(osdc, req, false);
 		if (!ret)
 			ret = ceph_osdc_wait_request(osdc, req);
+
+		ceph_update_read_latency(&fsc->mdsc->metric, req->r_start_stamp,
+					 req->r_end_stamp, ret);
+
 		ceph_osdc_put_request(req);
 
 		i_size = i_size_read(inode);
@@ -1044,6 +1048,8 @@ static void ceph_aio_complete_req(struct ceph_osd_request *req)
 	struct inode *inode = req->r_inode;
 	struct ceph_aio_request *aio_req = req->r_priv;
 	struct ceph_osd_data *osd_data = osd_req_op_extent_osd_data(req, 0);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_client_metric *metric = &fsc->mdsc->metric;
 
 	BUG_ON(osd_data->type != CEPH_OSD_DATA_TYPE_BVECS);
 	BUG_ON(!osd_data->num_bvecs);
@@ -1051,6 +1057,16 @@ static void ceph_aio_complete_req(struct ceph_osd_request *req)
 	dout("ceph_aio_complete_req %p rc %d bytes %u\n",
 	     inode, rc, osd_data->bvec_pos.iter.bi_size);
 
+	/* r_start_stamp == 0 means the request was not submitted */
+	if (req->r_start_stamp) {
+		if (aio_req->write)
+			ceph_update_write_latency(metric, req->r_start_stamp,
+						  req->r_end_stamp, rc);
+		else
+			ceph_update_read_latency(metric, req->r_start_stamp,
+						 req->r_end_stamp, rc);
+	}
+
 	if (rc == -EOLDSNAPC) {
 		struct ceph_aio_work *aio_work;
 		BUG_ON(!aio_req->write);
@@ -1179,6 +1195,7 @@ static void ceph_aio_retry_work(struct work_struct *work)
 	struct inode *inode = file_inode(file);
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct ceph_client_metric *metric = &fsc->mdsc->metric;
 	struct ceph_vino vino;
 	struct ceph_osd_request *req;
 	struct bio_vec *bvecs;
@@ -1295,6 +1312,13 @@ static void ceph_aio_retry_work(struct work_struct *work)
 		if (!ret)
 			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 
+		if (write)
+			ceph_update_write_latency(metric, req->r_start_stamp,
+						  req->r_end_stamp, ret);
+		else
+			ceph_update_read_latency(metric, req->r_start_stamp,
+						 req->r_end_stamp, ret);
+
 		size = i_size_read(inode);
 		if (!write) {
 			if (ret == -ENOENT)
@@ -1466,6 +1490,8 @@ static void ceph_aio_retry_work(struct work_struct *work)
 		if (!ret)
 			ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
 
+		ceph_update_write_latency(&fsc->mdsc->metric, req->r_start_stamp,
+					  req->r_end_stamp, ret);
 out:
 		ceph_osdc_put_request(req);
 		if (ret != 0) {
diff --git a/fs/ceph/metric.c b/fs/ceph/metric.c
index 2a4b739..4bf461d 100644
--- a/fs/ceph/metric.c
+++ b/fs/ceph/metric.c
@@ -2,6 +2,7 @@
 
 #include <linux/types.h>
 #include <linux/percpu_counter.h>
+#include <linux/math64.h>
 
 #include "metric.h"
 
@@ -29,8 +30,32 @@ int ceph_metric_init(struct ceph_client_metric *m)
 	if (ret)
 		goto err_i_caps_mis;
 
+	ret = percpu_counter_init(&m->read_latency_sq_sum, 0, GFP_KERNEL);
+	if (ret)
+		goto err_read_latency_sq_sum;
+
+	spin_lock_init(&m->read_latency_lock);
+	atomic64_set(&m->total_reads, 0);
+	atomic64_set(&m->read_latency_sum, 0);
+	atomic64_set(&m->read_latency_min, S64_MAX);
+	atomic64_set(&m->read_latency_max, 0);
+
+	ret = percpu_counter_init(&m->write_latency_sq_sum, 0, GFP_KERNEL);
+	if (ret)
+		goto err_write_latency_sq_sum;
+
+	spin_lock_init(&m->write_latency_lock);
+	atomic64_set(&m->total_writes, 0);
+	atomic64_set(&m->write_latency_sum, 0);
+	atomic64_set(&m->write_latency_min, S64_MAX);
+	atomic64_set(&m->write_latency_max, 0);
+
 	return 0;
 
+err_write_latency_sq_sum:
+	percpu_counter_destroy(&m->read_latency_sq_sum);
+err_read_latency_sq_sum:
+	percpu_counter_destroy(&m->i_caps_mis);
 err_i_caps_mis:
 	percpu_counter_destroy(&m->i_caps_hit);
 err_i_caps_hit:
@@ -46,8 +71,92 @@ void ceph_metric_destroy(struct ceph_client_metric *m)
 	if (!m)
 		return;
 
+	percpu_counter_destroy(&m->write_latency_sq_sum);
+	percpu_counter_destroy(&m->read_latency_sq_sum);
 	percpu_counter_destroy(&m->i_caps_mis);
 	percpu_counter_destroy(&m->i_caps_hit);
 	percpu_counter_destroy(&m->d_lease_mis);
 	percpu_counter_destroy(&m->d_lease_hit);
 }
+
+static inline void __update_min_latency(atomic64_t *min, unsigned long lat)
+{
+	unsigned long cur, old;
+
+	cur = atomic64_read(min);
+	do {
+		old = cur;
+		if (likely(lat >= old))
+			break;
+	} while (unlikely((cur = atomic64_cmpxchg(min, old, lat)) != old));
+}
+
+static inline void __update_max_latency(atomic64_t *max, unsigned long lat)
+{
+	unsigned long cur, old;
+
+	cur = atomic64_read(max);
+	do {
+		old = cur;
+		if (likely(lat <= old))
+			break;
+	} while (unlikely((cur = atomic64_cmpxchg(max, old, lat)) != old));
+}
+
+static inline void __update_avg_and_sq(atomic64_t *totalp, atomic64_t *lat_sump,
+				       struct percpu_counter *sq_sump,
+				       spinlock_t *lockp, unsigned long lat)
+{
+	s64 total, avg, sq, lsum;
+
+	spin_lock(lockp);
+	total = atomic64_inc_return(totalp);
+	lsum = atomic64_add_return(lat, lat_sump);
+	spin_unlock(lockp);
+
+	if (unlikely(total == 1))
+		return;
+
+	/* the sq is (lat - old_avg) * (lat - new_avg) */
+	avg = DIV64_U64_ROUND_CLOSEST((lsum - lat), (total - 1));
+	sq = lat - avg;
+	avg = DIV64_U64_ROUND_CLOSEST(lsum, total);
+	sq = sq * (lat - avg);
+	percpu_counter_add(sq_sump, sq);
+}
+
+void ceph_update_read_latency(struct ceph_client_metric *m,
+			      unsigned long r_start,
+			      unsigned long r_end,
+			      int rc)
+{
+	unsigned long lat = r_end - r_start;
+
+	if (unlikely(rc < 0 && rc != -ENOENT && rc != -ETIMEDOUT))
+		return;
+
+	__update_min_latency(&m->read_latency_min, lat);
+	__update_max_latency(&m->read_latency_max, lat);
+	__update_avg_and_sq(&m->total_reads, &m->read_latency_sum,
+			    &m->read_latency_sq_sum,
+			    &m->read_latency_lock,
+			    lat);
+}
+
+void ceph_update_write_latency(struct ceph_client_metric *m,
+			       unsigned long r_start,
+			       unsigned long r_end,
+			       int rc)
+{
+	unsigned long lat = r_end - r_start;
+
+	if (unlikely(rc && rc != -ETIMEDOUT))
+		return;
+
+	__update_min_latency(&m->write_latency_min, lat);
+	__update_max_latency(&m->write_latency_max, lat);
+	__update_avg_and_sq(&m->total_writes, &m->write_latency_sum,
+			    &m->write_latency_sq_sum,
+			    &m->write_latency_lock,
+			    lat);
+}
diff --git a/fs/ceph/metric.h b/fs/ceph/metric.h
index 098ee8a..a24482e 100644
--- a/fs/ceph/metric.h
+++ b/fs/ceph/metric.h
@@ -13,6 +13,20 @@ struct ceph_client_metric {
 
 	struct percpu_counter i_caps_hit;
 	struct percpu_counter i_caps_mis;
+
+	struct percpu_counter read_latency_sq_sum;
+	spinlock_t read_latency_lock;
+	atomic64_t total_reads;
+	atomic64_t read_latency_sum;
+	atomic64_t read_latency_min;
+	atomic64_t read_latency_max;
+
+	struct percpu_counter write_latency_sq_sum;
+	spinlock_t write_latency_lock;
+	atomic64_t total_writes;
+	atomic64_t write_latency_sum;
+	atomic64_t write_latency_min;
+	atomic64_t write_latency_max;
 };
 
 extern int ceph_metric_init(struct ceph_client_metric *m);
@@ -27,4 +41,13 @@ static inline void ceph_update_cap_mis(struct ceph_client_metric *m)
 {
 	percpu_counter_inc(&m->i_caps_mis);
 }
+
+extern void ceph_update_read_latency(struct ceph_client_metric *m,
+				     unsigned long r_start,
+				     unsigned long r_end,
+				     int rc);
+extern void ceph_update_write_latency(struct ceph_client_metric *m,
+				      unsigned long r_start,
+				      unsigned long r_end,
+				      int rc);
 #endif /* _FS_CEPH_MDS_METRIC_H */
diff --git a/include/linux/ceph/osd_client.h b/include/linux/ceph/osd_client.h
index 9d9f745..02ff3a3 100644
--- a/include/linux/ceph/osd_client.h
+++ b/include/linux/ceph/osd_client.h
@@ -213,6 +213,7 @@ struct ceph_osd_request {
 	/* internal */
 	unsigned long r_stamp;                /* jiffies, send or check time */
 	unsigned long r_start_stamp;          /* jiffies */
+	unsigned long r_end_stamp;            /* jiffies */
 	int r_attempts;
 	u32 r_map_dne_bound;
 
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 998e26b..28e33e0 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -2389,6 +2389,8 @@ static void finish_request(struct ceph_osd_request *req)
 	WARN_ON(lookup_request_mc(&osdc->map_checks, req->r_tid));
 	dout("%s req %p tid %llu\n", __func__, req, req->r_tid);
 
+	req->r_end_stamp = jiffies;
+
 	if (req->r_osd)
 		unlink_request(req->r_osd, req);
 	atomic_dec(&osdc->num_requests);
