In interrupt handler, prefetch the first incoming ring element
so that it is in cache by the time NAPI poll gets to it.
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
---
drivers/net/hyperv/netvsc.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0a9d9feedc3f..06f39a99da7c 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -30,6 +30,7 @@
#include <linux/if_ether.h>
#include <linux/vmalloc.h>
#include <linux/rtnetlink.h>
+#include <linux/prefetch.h>
#include <asm/sync_bitops.h>
@@ -1265,10 +1266,15 @@ int netvsc_poll(struct napi_struct *napi, int budget)
void netvsc_channel_cb(void *context)
{
struct netvsc_channel *nvchan = context;
+ struct vmbus_channel *channel = nvchan->channel;
+ struct hv_ring_buffer_info *rbi = &channel->inbound;
+
+ /* preload first vmpacket descriptor */
+ prefetch(hv_get_ring_buffer(rbi) + rbi->priv_read_index);
if (napi_schedule_prep(&nvchan->napi)) {
/* disable interupts from host */
- hv_begin_read(&nvchan->channel->inbound);
+ hv_begin_read(rbi);
__napi_schedule(&nvchan->napi);
}
--
2.11.0
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