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Date: Wed, 25 Aug 2010 23:15:11 +0200
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, herbert@...dor.apana.org.au
Subject: Re: [PATCH net-next-2.6] gro: __napi_gro_receive() optimizations
Le mercredi 25 août 2010 à 13:57 -0700, David Miller a écrit :
> From: Eric Dumazet <eric.dumazet@...il.com>
> Date: Wed, 25 Aug 2010 22:33:51 +0200
>
> > @@ -102,19 +102,9 @@ vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
> > if (vlan_dev)
> > skb->dev = vlan_dev;
> > else if (vlan_id)
> > - goto drop;
> > -
> > - for (p = napi->gro_list; p; p = p->next) {
> > - NAPI_GRO_CB(p)->same_flow =
> > - p->dev == skb->dev && !compare_ether_header(
> > - skb_mac_header(p), skb_gro_mac_header(skb));
> > - NAPI_GRO_CB(p)->flush = 0;
> > - }
> > -
> > - return dev_gro_receive(napi, skb);
> > + return GRO_DROP;
> >
> > -drop:
> > - return GRO_DROP;
> > + return __napi_gro_receive(napi, skb);
>
> I was looking at this the other day and considering something
> similar but I didn't do it because this now makes the call chain
> deeper.
>
> And that can make a performance difference.
>
> I don't want to add this hunk unless some GRO perf regression tests
> are done.
>
Yes, we can inline it, this will speedup the non vlan case as well :)
Thanks !
[PATCH net-next-2.6 v2] gro: __napi_gro_receive() optimizations
compare_ether_header() can have a special implementation on 64 bit
arches if CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is defined
__napi_gro_receive() can avoid a conditional branch to perform device
match.
__napi_gro_receive() can be used from vlan_gro_common() instead of being
duplicated.
As David requested, make it an inline function so that no extra level is
added in call chain.
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
---
include/linux/etherdevice.h | 27 ++++++++++++++++++++++++++-
net/8021q/vlan_core.c | 15 ++-------------
net/core/dev.c | 16 ----------------
3 files changed, 28 insertions(+), 30 deletions(-)
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 2308fbb..9c58d68 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -237,13 +237,38 @@ static inline bool is_etherdev_addr(const struct net_device *dev,
* entry points.
*/
-static inline int compare_ether_header(const void *a, const void *b)
+static inline unsigned long compare_ether_header(const void *a, const void *b)
{
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
+ unsigned long fold;
+
+ fold = *(unsigned long *)a ^ *(unsigned long *)b;
+ fold |= *(unsigned long *)(a + 6) ^ *(unsigned long *)(b + 6);
+ return fold;
+#else
u32 *a32 = (u32 *)((u8 *)a + 2);
u32 *b32 = (u32 *)((u8 *)b + 2);
return (*(u16 *)a ^ *(u16 *)b) | (a32[0] ^ b32[0]) |
(a32[1] ^ b32[1]) | (a32[2] ^ b32[2]);
+#endif
+}
+
+static inline gro_result_t __napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
+{
+ struct sk_buff *p;
+
+ for (p = napi->gro_list; p; p = p->next) {
+ unsigned long diffs;
+
+ diffs = (unsigned long)p->dev ^ (unsigned long)skb->dev;
+ diffs |= compare_ether_header(skb_mac_header(p),
+ skb_gro_mac_header(skb));
+ NAPI_GRO_CB(p)->same_flow = !diffs;
+ NAPI_GRO_CB(p)->flush = 0;
+ }
+
+ return dev_gro_receive(napi, skb);
}
#endif /* _LINUX_ETHERDEVICE_H */
diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 07eeb5b..ce7b4b1 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -87,7 +87,6 @@ static gro_result_t
vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
unsigned int vlan_tci, struct sk_buff *skb)
{
- struct sk_buff *p;
struct net_device *vlan_dev;
u16 vlan_id;
@@ -102,19 +101,9 @@ vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
if (vlan_dev)
skb->dev = vlan_dev;
else if (vlan_id)
- goto drop;
-
- for (p = napi->gro_list; p; p = p->next) {
- NAPI_GRO_CB(p)->same_flow =
- p->dev == skb->dev && !compare_ether_header(
- skb_mac_header(p), skb_gro_mac_header(skb));
- NAPI_GRO_CB(p)->flush = 0;
- }
-
- return dev_gro_receive(napi, skb);
+ return GRO_DROP;
-drop:
- return GRO_DROP;
+ return __napi_gro_receive(napi, skb);
}
gro_result_t vlan_gro_receive(struct napi_struct *napi, struct vlan_group *grp,
diff --git a/net/core/dev.c b/net/core/dev.c
index 859e30f..195f9c7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3169,22 +3169,6 @@ normal:
}
EXPORT_SYMBOL(dev_gro_receive);
-static gro_result_t
-__napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
-{
- struct sk_buff *p;
-
- for (p = napi->gro_list; p; p = p->next) {
- NAPI_GRO_CB(p)->same_flow =
- (p->dev == skb->dev) &&
- !compare_ether_header(skb_mac_header(p),
- skb_gro_mac_header(skb));
- NAPI_GRO_CB(p)->flush = 0;
- }
-
- return dev_gro_receive(napi, skb);
-}
-
gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
{
switch (ret) {
--
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