qlge: Optimize rx buffer refill process.
Ron Mercer [Mon, 23 Feb 2009 10:42:16 +0000 (10:42 +0000)]
RX Buffers are refilled in chunks of 16 at a time before notifying the
hardware with a register write.  This can cause several writes to take
place in a given napi poll call.  This change causes the write to take place
only once at the end of the call.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/qlge/qlge_main.c

index 16c056a..1719845 100644 (file)
@@ -863,7 +863,8 @@ static void ql_write_cq_idx(struct rx_ring *rx_ring)
 /* Process (refill) a large buffer queue. */
 static void ql_update_lbq(struct ql_adapter *qdev, struct rx_ring *rx_ring)
 {
-       int clean_idx = rx_ring->lbq_clean_idx;
+       u32 clean_idx = rx_ring->lbq_clean_idx;
+       u32 start_idx = clean_idx;
        struct bq_desc *lbq_desc;
        u64 map;
        int i;
@@ -910,19 +911,23 @@ static void ql_update_lbq(struct ql_adapter *qdev, struct rx_ring *rx_ring)
                rx_ring->lbq_prod_idx += 16;
                if (rx_ring->lbq_prod_idx == rx_ring->lbq_len)
                        rx_ring->lbq_prod_idx = 0;
+               rx_ring->lbq_free_cnt -= 16;
+       }
+
+       if (start_idx != clean_idx) {
                QPRINTK(qdev, RX_STATUS, DEBUG,
                        "lbq: updating prod idx = %d.\n",
                        rx_ring->lbq_prod_idx);
                ql_write_db_reg(rx_ring->lbq_prod_idx,
                                rx_ring->lbq_prod_idx_db_reg);
-               rx_ring->lbq_free_cnt -= 16;
        }
 }
 
 /* Process (refill) a small buffer queue. */
 static void ql_update_sbq(struct ql_adapter *qdev, struct rx_ring *rx_ring)
 {
-       int clean_idx = rx_ring->sbq_clean_idx;
+       u32 clean_idx = rx_ring->sbq_clean_idx;
+       u32 start_idx = clean_idx;
        struct bq_desc *sbq_desc;
        u64 map;
        int i;
@@ -972,13 +977,15 @@ static void ql_update_sbq(struct ql_adapter *qdev, struct rx_ring *rx_ring)
                rx_ring->sbq_prod_idx += 16;
                if (rx_ring->sbq_prod_idx == rx_ring->sbq_len)
                        rx_ring->sbq_prod_idx = 0;
+               rx_ring->sbq_free_cnt -= 16;
+       }
+
+       if (start_idx != clean_idx) {
                QPRINTK(qdev, RX_STATUS, DEBUG,
                        "sbq: updating prod idx = %d.\n",
                        rx_ring->sbq_prod_idx);
                ql_write_db_reg(rx_ring->sbq_prod_idx,
                                rx_ring->sbq_prod_idx_db_reg);
-
-               rx_ring->sbq_free_cnt -= 16;
        }
 }