From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santiago Leon Subject: [patch 08/21] ibmveth: Add optional flush of rx buffer Date: Fri, 03 Sep 2010 23:28:41 -0500 Message-ID: <20100904042841.2655.69990.sendpatchset@jupiter1-ltc-lp2.austin.ibm.com> References: <20100904042758.2655.8093.sendpatchset@jupiter1-ltc-lp2.austin.ibm.com> Cc: brking@linux.vnet.ibm.com, Santiago Leon , anton@samba.org To: netdev@vger.kernel.org Return-path: Received: from e37.co.us.ibm.com ([32.97.110.158]:41699 "EHLO e37.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752312Ab0IDE3K (ORCPT ); Sat, 4 Sep 2010 00:29:10 -0400 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e37.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id o844R9JC003619 for ; Fri, 3 Sep 2010 22:27:09 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id o844T93b227102 for ; Fri, 3 Sep 2010 22:29:09 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o844T9vB000354 for ; Fri, 3 Sep 2010 22:29:09 -0600 In-Reply-To: <20100904042758.2655.8093.sendpatchset@jupiter1-ltc-lp2.austin.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: On some machines we can improve the bandwidth by ensuring rx buffers are not in the cache. Add a module option that is disabled by default that flushes rx buffers on insertion. Signed-off-by: Anton Blanchard Signed-off-by: Santiago Leon --- Index: net-next-2.6/drivers/net/ibmveth.c =================================================================== --- net-next-2.6.orig//drivers/net/ibmveth.c 2010-09-03 22:18:54.000000000 -0500 +++ net-next-2.6/drivers/net/ibmveth.c 2010-09-03 22:18:54.000000000 -0500 @@ -127,6 +127,10 @@ module_param(rx_copybreak, uint, 0644); MODULE_PARM_DESC(rx_copybreak, "Maximum size of packet that is copied to a new buffer on receive"); +static unsigned int rx_flush __read_mostly = 0; +module_param(rx_flush, uint, 0644); +MODULE_PARM_DESC(rx_flush, "Flush receive buffers before use"); + struct ibmveth_stat { char name[ETH_GSTRING_LEN]; int offset; @@ -234,6 +238,14 @@ static int ibmveth_alloc_buffer_pool(str return 0; } +static inline void ibmveth_flush_buffer(void *addr, unsigned long length) +{ + unsigned long offset; + + for (offset = 0; offset < length; offset += SMP_CACHE_BYTES) + asm("dcbfl %0,%1" :: "b" (addr), "r" (offset)); +} + /* replenish the buffers for a pool. note that we don't need to * skb_reserve these since they are used for incoming... */ @@ -286,6 +298,12 @@ static void ibmveth_replenish_buffer_poo desc.fields.flags_len = IBMVETH_BUF_VALID | pool->buff_size; desc.fields.address = dma_addr; + if (rx_flush) { + unsigned int len = min(pool->buff_size, + adapter->netdev->mtu + + IBMVETH_BUFF_OH); + ibmveth_flush_buffer(skb->data, len); + } lpar_rc = h_add_logical_lan_buffer(adapter->vdev->unit_address, desc.desc); if (lpar_rc != H_SUCCESS) @@ -1095,6 +1113,9 @@ static int ibmveth_poll(struct napi_stru skb_copy_to_linear_data(new_skb, skb->data + offset, length); + if (rx_flush) + ibmveth_flush_buffer(skb->data, + length + offset); skb = new_skb; ibmveth_rxq_recycle_buffer(adapter); } else {