From 0c26b6775f36ce447722e8752bc3a006ec832df3 Mon Sep 17 00:00:00 2001 From: Santiago Leon Date: Fri, 3 Sep 2010 18:28:41 +0000 Subject: [PATCH] ibmveth: Add optional flush of rx buffer 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 Signed-off-by: David S. Miller --- drivers/net/ibmveth.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c index d8a8984..1685e23 100644 --- a/drivers/net/ibmveth.c +++ b/drivers/net/ibmveth.c @@ -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(struct ibmveth_buff_pool *pool) 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_pool(struct ibmveth_adapter *adapter, struc 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_struct *napi, int budget) 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 { -- 2.7.4