From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kok, Auke" Subject: [PATCH 20/22] e1000: Fix poor quad port performance with NAPI Date: Fri, 08 Dec 2006 15:03:29 -0800 Message-ID: <20061208230329.30109.85896.stgit@gitlost.site> References: <20061208230209.30109.49157.stgit@gitlost.site> Cc: netdev@vger.kernel.org, "Brandeburg, Jesse" , "Kok, Auke" , "Kok, Auke" , "Ronciak, John" Return-path: Received: from [63.64.152.142] ([63.64.152.142]:4396 "EHLO gitlost.site" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1947468AbWLHWyB (ORCPT ); Fri, 8 Dec 2006 17:54:01 -0500 To: "Garzik, Jeff" In-Reply-To: <20061208230209.30109.49157.stgit@gitlost.site> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This fix attempts to solve a customer reported issue with NAPI enabled e1000 having bad performance when transmitting simultaneously on four ports. The issue comes down to an interaction between NAPI hardware interrupt balancing, and the driver rescheduling poll on the same processor. We try to fix by allowing the driver to re-enable interrupts sooner instead of polling one more time, when there was recently all the work completed in cleanup. Signed-off-by: Jesse Brandeburg Signed-off-by: Auke Kok --- drivers/net/e1000/e1000_main.c | 25 ++++++++++++++++--------- 1 files changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c index 1a2b052..458aa38 100644 --- a/drivers/net/e1000/e1000_main.c +++ b/drivers/net/e1000/e1000_main.c @@ -3826,7 +3826,7 @@ e1000_intr_msi(int irq, void *data) for (i = 0; i < E1000_MAX_INTR; i++) if (unlikely(!adapter->clean_rx(adapter, adapter->rx_ring) & - !e1000_clean_tx_irq(adapter, adapter->tx_ring))) + e1000_clean_tx_irq(adapter, adapter->tx_ring))) break; if (likely(adapter->itr_setting & 3)) @@ -3979,7 +3979,7 @@ e1000_clean(struct net_device *poll_dev, poll_dev->quota -= work_done; /* If no Tx and not enough Rx work done, exit the polling mode */ - if ((!tx_cleaned && (work_done == 0)) || + if ((tx_cleaned && (work_done < work_to_do)) || !netif_running(poll_dev)) { quit_polling: if (likely(adapter->itr_setting & 3)) @@ -4009,7 +4009,7 @@ e1000_clean_tx_irq(struct e1000_adapter #ifdef CONFIG_E1000_NAPI unsigned int count = 0; #endif - boolean_t cleaned = FALSE; + boolean_t cleaned = TRUE; unsigned int total_tx_bytes=0, total_tx_packets=0; i = tx_ring->next_to_clean; @@ -4025,13 +4025,17 @@ e1000_clean_tx_irq(struct e1000_adapter if (cleaned) { struct sk_buff *skb = buffer_info->skb; #ifdef NETIF_F_TSO - unsigned int segs = skb_shinfo(skb)->gso_segs; - if (segs) - total_tx_packets += segs; -#endif - + unsigned int segs, bytecount; + segs = skb_shinfo(skb)->gso_segs ?: 1; + /* multiply data chunks by size of headers */ + bytecount = ((segs - 1) * skb_headlen(skb)) + + skb->len; + total_tx_packets += segs; + total_tx_bytes += bytecount; +#else total_tx_packets++; total_tx_bytes += skb->len; +#endif } e1000_unmap_and_free_tx_resource(adapter, buffer_info); tx_desc->upper.data = 0; @@ -4044,7 +4048,10 @@ e1000_clean_tx_irq(struct e1000_adapter #ifdef CONFIG_E1000_NAPI #define E1000_TX_WEIGHT 64 /* weight of a sort for tx, to avoid endless transmit cleanup */ - if (count++ == E1000_TX_WEIGHT) break; + if (count++ == E1000_TX_WEIGHT) { + cleaned = FALSE; + break; + } #endif } --- Auke Kok