From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx>
When iterating over incoming ring elements from the host, prefetch
the next descriptor so that it is cache hot.
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
---
drivers/hv/ring_buffer.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 741daa6..12eb8ca 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -357,11 +357,16 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel)
{
struct hv_ring_buffer_info *rbi = &channel->inbound;
+ struct vmpacket_descriptor *desc;
if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))
return NULL;
- return hv_get_ring_buffer(rbi) + rbi->priv_read_index;
+ desc = hv_get_ring_buffer(rbi) + rbi->priv_read_index;
+ if (desc)
+ prefetch((char *)desc + (desc->len8 << 3));
+
+ return desc;
}
EXPORT_SYMBOL_GPL(hv_pkt_iter_first);
--
1.7.1
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