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authorBenjamin LaHaise <ben.lahaise@neterion.com>2009-08-04 10:21:39 +0000
committerDavid S. Miller <davem@davemloft.net>2009-08-05 13:10:45 -0700
commit3f23e436d241ac1cf50a659228a5a0e1e6572c1a (patch)
treeeca045a10b9d536362f3a4f654da5c740a416e85
parentff1b974cf30b282f90993ab658e59b73c152c0b8 (diff)
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 <ben.lahaise@neterion.com> Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com> Signed-off-by: Ramkrishna Vepa <ram.vepa@neterion.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/vxge/vxge-main.c1
-rw-r--r--drivers/net/vxge/vxge-traffic.c1
2 files changed, 2 insertions, 0 deletions
diff --git a/drivers/net/vxge/vxge-main.c b/drivers/net/vxge/vxge-main.c
index 4b22513bed4..e93651c19f5 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 0efb769894e..fe3ae518c69 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);
}
/*