be2net: cleanup rx/tx rate calculations

Hi, Pls accept this patch to cleanup rx/tx rate calculations as follows:
- check for jiffies wraparound
- remove typecast of a denominator
- do rate calculation only in workqueue context periodically

Signed-off-by: Sathya Perla <sathyap@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 72 insertions, 36 deletions

diff --git a/drivers/net/benet/be.h b/drivers/net/benet/be.h
index f327be57ca96..c49ddd08b2aa 100644
--- a/drivers/net/benet/be.h
+++ b/drivers/net/benet/be.h
@@ -100,9 +100,9 @@ struct be_drvr_stats {
         u32 be_tx_wrbs;         /* number of tx WRBs used */
         u32 be_tx_events;       /* number of tx completion events  */
         u32 be_tx_compl;        /* number of tx completion entries processed */
-        u64 be_tx_jiffies;
-        ulong be_tx_bytes;
-        ulong be_tx_bytes_prev;
+        ulong be_tx_jiffies;
+        u64 be_tx_bytes;
+        u64 be_tx_bytes_prev;
         u32 be_tx_rate;
 
         u32 cache_barrier[16];
@@ -113,9 +113,9 @@ struct be_drvr_stats {
         u32 be_rx_compl;        /* number of rx completion entries processed */
         u32 be_lro_hgram_data[8];       /* histogram of LRO data packets */
         u32 be_lro_hgram_ack[8];        /* histogram of LRO ACKs */
-        u64 be_rx_jiffies;
-        ulong be_rx_bytes;
-        ulong be_rx_bytes_prev;
+        ulong be_rx_jiffies;
+        u64 be_rx_bytes;
+        u64 be_rx_bytes_prev;
         u32 be_rx_rate;
         /* number of non ether type II frames dropped where
          * frame len > length field of Mac Hdr */
diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 0ecaffb70e58..f901fee79a20 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -245,19 +245,29 @@ static void be_link_status_update(struct be_adapter *adapter)
 /* Update the EQ delay n BE based on the RX frags consumed / sec */
 static void be_rx_eqd_update(struct be_adapter *adapter)
 {
-        u32 eqd;
         struct be_ctrl_info *ctrl = &adapter->ctrl;
         struct be_eq_obj *rx_eq = &adapter->rx_eq;
         struct be_drvr_stats *stats = &adapter->stats.drvr_stats;
+        ulong now = jiffies;
+        u32 eqd;
+
+        if (!rx_eq->enable_aic)
+                return;
+
+        /* Wrapped around */
+        if (time_before(now, stats->rx_fps_jiffies)) {
+                stats->rx_fps_jiffies = now;
+                return;
+        }
 
         /* Update once a second */
-        if (((jiffies - stats->rx_fps_jiffies) < HZ) || rx_eq->enable_aic == 0)
+        if ((now - stats->rx_fps_jiffies) < HZ)
                 return;
 
         stats->be_rx_fps = (stats->be_rx_frags - stats->be_prev_rx_frags) /
-                        ((jiffies - stats->rx_fps_jiffies) / HZ);
+                        ((now - stats->rx_fps_jiffies) / HZ);
 
-        stats->rx_fps_jiffies = jiffies;
+        stats->rx_fps_jiffies = now;
         stats->be_prev_rx_frags = stats->be_rx_frags;
         eqd = stats->be_rx_fps / 110000;
         eqd = eqd << 3;
@@ -280,26 +290,38 @@ static struct net_device_stats *be_get_stats(struct net_device *dev)
         return &adapter->stats.net_stats;
 }
 
+static void be_tx_rate_update(struct be_adapter *adapter)
+{
+        struct be_drvr_stats *stats = drvr_stats(adapter);
+        ulong now = jiffies;
+
+        /* Wrapped around? */
+        if (time_before(now, stats->be_tx_jiffies)) {
+                stats->be_tx_jiffies = now;
+                return;
+        }
+
+        /* Update tx rate once in two seconds */
+        if ((now - stats->be_tx_jiffies) > 2 * HZ) {
+                u32 r;
+                r = (stats->be_tx_bytes - stats->be_tx_bytes_prev) /
+                        ((now - stats->be_tx_jiffies) / HZ);
+                r = r / 1000000;                        /* M bytes/s */
+                stats->be_tx_rate = r * 8;      /* M bits/s */
+                stats->be_tx_jiffies = now;
+                stats->be_tx_bytes_prev = stats->be_tx_bytes;
+        }
+}
+
 static void be_tx_stats_update(struct be_adapter *adapter,
                         u32 wrb_cnt, u32 copied, bool stopped)
 {
-        struct be_drvr_stats *stats = &adapter->stats.drvr_stats;
+        struct be_drvr_stats *stats = drvr_stats(adapter);
         stats->be_tx_reqs++;
         stats->be_tx_wrbs += wrb_cnt;
         stats->be_tx_bytes += copied;
         if (stopped)
                 stats->be_tx_stops++;
-
-        /* Update tx rate once in two seconds */
-        if ((jiffies - stats->be_tx_jiffies) > 2 * HZ) {
-                u32 r;
-                r = (stats->be_tx_bytes - stats->be_tx_bytes_prev) /
-                        ((u32) (jiffies - stats->be_tx_jiffies) / HZ);
-                r = (r / 1000000);                      /* M bytes/s */
-                stats->be_tx_rate = (r * 8);    /* M bits/s */
-                stats->be_tx_jiffies = jiffies;
-                stats->be_tx_bytes_prev = stats->be_tx_bytes;
-        }
 }
 
 /* Determine number of WRB entries needed to xmit data in an skb */
@@ -573,28 +595,40 @@ static void be_set_multicast_list(struct net_device *netdev)
         }
 }
 
-static void be_rx_rate_update(struct be_adapter *adapter, u32 pktsize,
-                        u16 numfrags)
+static void be_rx_rate_update(struct be_adapter *adapter)
 {
-        struct be_drvr_stats *stats = &adapter->stats.drvr_stats;
+        struct be_drvr_stats *stats = drvr_stats(adapter);
+        ulong now = jiffies;
         u32 rate;
 
-        stats->be_rx_compl++;
-        stats->be_rx_frags += numfrags;
-        stats->be_rx_bytes += pktsize;
+        /* Wrapped around */
+        if (time_before(now, stats->be_rx_jiffies)) {
+                stats->be_rx_jiffies = now;
+                return;
+        }
 
         /* Update the rate once in two seconds */
-        if ((jiffies - stats->be_rx_jiffies) < 2 * HZ)
+        if ((now - stats->be_rx_jiffies) < 2 * HZ)
                 return;
 
         rate = (stats->be_rx_bytes - stats->be_rx_bytes_prev) /
-                ((u32) (jiffies - stats->be_rx_jiffies) / HZ);
-        rate = (rate / 1000000);        /* MB/Sec */
-        stats->be_rx_rate = (rate * 8);         /* Mega Bits/Sec */
-        stats->be_rx_jiffies = jiffies;
+                ((now - stats->be_rx_jiffies) / HZ);
+        rate = rate / 1000000;  /* MB/Sec */
+        stats->be_rx_rate = rate * 8;   /* Mega Bits/Sec */
+        stats->be_rx_jiffies = now;
         stats->be_rx_bytes_prev = stats->be_rx_bytes;
 }
 
+static void be_rx_stats_update(struct be_adapter *adapter,
+                u32 pktsize, u16 numfrags)
+{
+        struct be_drvr_stats *stats = drvr_stats(adapter);
+
+        stats->be_rx_compl++;
+        stats->be_rx_frags += numfrags;
+        stats->be_rx_bytes += pktsize;
+}
+
 static struct be_rx_page_info *
 get_rx_page_info(struct be_adapter *adapter, u16 frag_idx)
 {
@@ -700,7 +734,7 @@ static void skb_fill_rx_data(struct be_adapter *adapter,
                 memset(page_info, 0, sizeof(*page_info));
         }
 
-        be_rx_rate_update(adapter, pktsize, num_rcvd);
+        be_rx_stats_update(adapter, pktsize, num_rcvd);
         return;
 }
 
@@ -799,7 +833,7 @@ static void be_rx_compl_process_lro(struct be_adapter *adapter,
                         vid, NULL, 0);
         }
 
-        be_rx_rate_update(adapter, pkt_size, num_rcvd);
+        be_rx_stats_update(adapter, pkt_size, num_rcvd);
         return;
 }
 
@@ -841,7 +875,6 @@ static void be_post_rx_frags(struct be_adapter *adapter)
         u64 page_dmaaddr = 0, frag_dmaaddr;
         u32 posted, page_offset = 0;
 
-
         page_info = &page_info_tbl[rxq->head];
         for (posted = 0; posted < MAX_RX_POST && !page_info->page; posted++) {
                 if (!pagep) {
@@ -1305,6 +1338,9 @@ static void be_worker(struct work_struct *work)
         /* Set EQ delay */
         be_rx_eqd_update(adapter);
 
+        be_tx_rate_update(adapter);
+        be_rx_rate_update(adapter);
+
         if (adapter->rx_post_starved) {
                 adapter->rx_post_starved = false;
                 be_post_rx_frags(adapter);