From 3f23e436d241ac1cf50a659228a5a0e1e6572c1a Mon Sep 17 00:00:00 2001 From: Benjamin LaHaise Date: Tue, 4 Aug 2009 10:21:39 +0000 Subject: [PATCH] vxge: prefetch RxD descriptors This patch prefetches RxD descriptors which helps to lower the latency of a cache miss in vxge_hw_ring_rxd_next_completed. This lowers the % of CPU time used by vxge_hw_ring_rxd_next_completed() where the descriptor is accessed in profiling netperf on a P4 Xeon from 1.5% to 1.0%. Signed-off-by: Benjamin LaHaise Signed-off-by: Sreenivasa Honnur Signed-off-by: Ramkrishna Vepa Signed-off-by: David S. Miller --- drivers/net/vxge/vxge-main.c | 1 + drivers/net/vxge/vxge-traffic.c | 1 + 2 files changed, 2 insertions(+) diff --git a/drivers/net/vxge/vxge-main.c b/drivers/net/vxge/vxge-main.c index 4b22513bed40..e93651c19f59 100644 --- a/drivers/net/vxge/vxge-main.c +++ b/drivers/net/vxge/vxge-main.c @@ -445,6 +445,7 @@ vxge_rx_1b_compl(struct __vxge_hw_ring *ringh, void *dtr, vxge_hw_ring_replenish(ringh, 0); do { + prefetch((char *)dtr + L1_CACHE_BYTES); rx_priv = vxge_hw_ring_rxd_private_get(dtr); skb = rx_priv->skb; data_size = rx_priv->data_size; diff --git a/drivers/net/vxge/vxge-traffic.c b/drivers/net/vxge/vxge-traffic.c index 0efb769894ef..fe3ae518c69c 100644 --- a/drivers/net/vxge/vxge-traffic.c +++ b/drivers/net/vxge/vxge-traffic.c @@ -731,6 +731,7 @@ vxge_hw_channel_dtr_try_complete(struct __vxge_hw_channel *channel, void **dtrh) vxge_assert(channel->compl_index < channel->length); *dtrh = channel->work_arr[channel->compl_index]; + prefetch(*dtrh); } /* -- GitLab