* [PATCH net-next 0/2] gro: a couple of minor optimization
@ 2022-02-04 11:28 Paolo Abeni
2022-02-04 11:28 ` [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle Paolo Abeni
` (5 more replies)
0 siblings, 6 replies; 9+ messages in thread
From: Paolo Abeni @ 2022-02-04 11:28 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Jakub Kicinski, Alexander Lobakin, Eric Dumazet,
Alexander H Duyck
This series collects a couple of small optimizations for the GRO engine,
reducing slightly the number of cycles for dev_gro_receive().
The delta is within noise range in tput tests, but with big TCP coming
every cycle saved from the GRO engine will count - I hope ;)
v1 -> v2:
- a few cleanup suggested from Alexander(s)
- moved away the more controversial 3rd patch
Paolo Abeni (2):
net: gro: avoid re-computing truesize twice on recycle
net: gro: minor optimization for dev_gro_receive()
include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
net/core/gro.c | 16 ++++-----------
2 files changed, 32 insertions(+), 36 deletions(-)
--
2.34.1
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
@ 2022-02-04 11:28 ` Paolo Abeni
2022-02-04 16:34 ` Eric Dumazet
2022-02-04 11:28 ` [PATCH net-next 2/2] net: gro: minor optimization for dev_gro_receive() Paolo Abeni
` (4 subsequent siblings)
5 siblings, 1 reply; 9+ messages in thread
From: Paolo Abeni @ 2022-02-04 11:28 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Jakub Kicinski, Alexander Lobakin, Eric Dumazet,
Alexander H Duyck
After commit 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb
carring sock reference") and commit af352460b465 ("net: fix GRO
skb truesize update") the truesize of the skb with stolen head is
properly updated by the GRO engine, we don't need anymore resetting
it at recycle time.
v1 -> v2:
- clarify the commit message (Alexander)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/core/gro.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/net/core/gro.c b/net/core/gro.c
index a11b286d1495..d43d42215bdb 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -634,7 +634,6 @@ static void napi_reuse_skb(struct napi_struct *napi, struct sk_buff *skb)
skb->encapsulation = 0;
skb_shinfo(skb)->gso_type = 0;
- skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));
if (unlikely(skb->slow_gro)) {
skb_orphan(skb);
skb_ext_reset(skb);
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH net-next 2/2] net: gro: minor optimization for dev_gro_receive()
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
2022-02-04 11:28 ` [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle Paolo Abeni
@ 2022-02-04 11:28 ` Paolo Abeni
2022-02-04 11:34 ` [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
` (3 subsequent siblings)
5 siblings, 0 replies; 9+ messages in thread
From: Paolo Abeni @ 2022-02-04 11:28 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Jakub Kicinski, Alexander Lobakin, Eric Dumazet,
Alexander H Duyck
While inspecting some perf report, I noticed that the compiler
emits suboptimal code for the napi CB initialization, fetching
and storing multiple times the memory for flags bitfield.
This is with gcc 10.3.1, but I observed the same with older compiler
versions.
We can help the compiler to do a nicer work clearing several
fields at once using an u32 alias. The generated code is quite
smaller, with the same number of conditional.
Before:
objdump -t net/core/gro.o | grep " F .text"
0000000000000bb0 l F .text 0000000000000357 dev_gro_receive
After:
0000000000000bb0 l F .text 000000000000033c dev_gro_receive
v1 -> v2:
- use struct_group (Alexander and Alex)
RFC -> v1:
- use __struct_group to delimit the zeroed area (Alexander)
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
net/core/gro.c | 15 ++++----------
2 files changed, 32 insertions(+), 35 deletions(-)
diff --git a/include/net/gro.h b/include/net/gro.h
index 8f75802d50fd..a765fedda5c4 100644
--- a/include/net/gro.h
+++ b/include/net/gro.h
@@ -29,46 +29,50 @@ struct napi_gro_cb {
/* Number of segments aggregated. */
u16 count;
- /* Start offset for remote checksum offload */
- u16 gro_remcsum_start;
+ /* Used in ipv6_gro_receive() and foo-over-udp */
+ u16 proto;
/* jiffies when first packet was created/queued */
unsigned long age;
- /* Used in ipv6_gro_receive() and foo-over-udp */
- u16 proto;
+ /* portion of the cb set to zero at every gro iteration */
+ struct_group(zeroed,
+
+ /* Start offset for remote checksum offload */
+ u16 gro_remcsum_start;
- /* This is non-zero if the packet may be of the same flow. */
- u8 same_flow:1;
+ /* This is non-zero if the packet may be of the same flow. */
+ u8 same_flow:1;
- /* Used in tunnel GRO receive */
- u8 encap_mark:1;
+ /* Used in tunnel GRO receive */
+ u8 encap_mark:1;
- /* GRO checksum is valid */
- u8 csum_valid:1;
+ /* GRO checksum is valid */
+ u8 csum_valid:1;
- /* Number of checksums via CHECKSUM_UNNECESSARY */
- u8 csum_cnt:3;
+ /* Number of checksums via CHECKSUM_UNNECESSARY */
+ u8 csum_cnt:3;
- /* Free the skb? */
- u8 free:2;
+ /* Free the skb? */
+ u8 free:2;
#define NAPI_GRO_FREE 1
#define NAPI_GRO_FREE_STOLEN_HEAD 2
- /* Used in foo-over-udp, set in udp[46]_gro_receive */
- u8 is_ipv6:1;
+ /* Used in foo-over-udp, set in udp[46]_gro_receive */
+ u8 is_ipv6:1;
- /* Used in GRE, set in fou/gue_gro_receive */
- u8 is_fou:1;
+ /* Used in GRE, set in fou/gue_gro_receive */
+ u8 is_fou:1;
- /* Used to determine if flush_id can be ignored */
- u8 is_atomic:1;
+ /* Used to determine if flush_id can be ignored */
+ u8 is_atomic:1;
- /* Number of gro_receive callbacks this packet already went through */
- u8 recursion_counter:4;
+ /* Number of gro_receive callbacks this packet already went through */
+ u8 recursion_counter:4;
- /* GRO is done by frag_list pointer chaining. */
- u8 is_flist:1;
+ /* GRO is done by frag_list pointer chaining. */
+ u8 is_flist:1;
+ );
/* used to support CHECKSUM_COMPLETE for tunneling protocols */
__wsum csum;
diff --git a/net/core/gro.c b/net/core/gro.c
index d43d42215bdb..ee5e7e889d8b 100644
--- a/net/core/gro.c
+++ b/net/core/gro.c
@@ -459,29 +459,22 @@ static enum gro_result dev_gro_receive(struct napi_struct *napi, struct sk_buff
skb_set_network_header(skb, skb_gro_offset(skb));
skb_reset_mac_len(skb);
- NAPI_GRO_CB(skb)->same_flow = 0;
+ BUILD_BUG_ON(sizeof_field(struct napi_gro_cb, zeroed) != sizeof(u32));
+ BUILD_BUG_ON(!IS_ALIGNED(offsetof(struct napi_gro_cb, zeroed),
+ sizeof(u32))); /* Avoid slow unaligned acc */
+ *(u32 *)&NAPI_GRO_CB(skb)->zeroed = 0;
NAPI_GRO_CB(skb)->flush = skb_is_gso(skb) || skb_has_frag_list(skb);
- NAPI_GRO_CB(skb)->free = 0;
- NAPI_GRO_CB(skb)->encap_mark = 0;
- NAPI_GRO_CB(skb)->recursion_counter = 0;
- NAPI_GRO_CB(skb)->is_fou = 0;
NAPI_GRO_CB(skb)->is_atomic = 1;
- NAPI_GRO_CB(skb)->gro_remcsum_start = 0;
/* Setup for GRO checksum validation */
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
NAPI_GRO_CB(skb)->csum = skb->csum;
NAPI_GRO_CB(skb)->csum_valid = 1;
- NAPI_GRO_CB(skb)->csum_cnt = 0;
break;
case CHECKSUM_UNNECESSARY:
NAPI_GRO_CB(skb)->csum_cnt = skb->csum_level + 1;
- NAPI_GRO_CB(skb)->csum_valid = 0;
break;
- default:
- NAPI_GRO_CB(skb)->csum_cnt = 0;
- NAPI_GRO_CB(skb)->csum_valid = 0;
}
pp = INDIRECT_CALL_INET(ptype->callbacks.gro_receive,
--
2.34.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 0/2] gro: a couple of minor optimization
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
2022-02-04 11:28 ` [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle Paolo Abeni
2022-02-04 11:28 ` [PATCH net-next 2/2] net: gro: minor optimization for dev_gro_receive() Paolo Abeni
@ 2022-02-04 11:34 ` Paolo Abeni
2022-02-05 9:51 ` David Miller
2022-02-04 12:16 ` Alexander Lobakin
` (2 subsequent siblings)
5 siblings, 1 reply; 9+ messages in thread
From: Paolo Abeni @ 2022-02-04 11:34 UTC (permalink / raw)
To: netdev
Cc: David S. Miller, Jakub Kicinski, Alexander Lobakin, Eric Dumazet,
Alexander H Duyck
On Fri, 2022-02-04 at 12:28 +0100, Paolo Abeni wrote:
> This series collects a couple of small optimizations for the GRO engine,
> reducing slightly the number of cycles for dev_gro_receive().
> The delta is within noise range in tput tests, but with big TCP coming
> every cycle saved from the GRO engine will count - I hope ;)
>
> v1 -> v2:
> - a few cleanup suggested from Alexander(s)
> - moved away the more controversial 3rd patch
>
> Paolo Abeni (2):
> net: gro: avoid re-computing truesize twice on recycle
> net: gro: minor optimization for dev_gro_receive()
>
> include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
> net/core/gro.c | 16 ++++-----------
> 2 files changed, 32 insertions(+), 36 deletions(-)
This is really a v2. Please let me know if you prefer a formal repost.
Thanks!
Paolo
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 0/2] gro: a couple of minor optimization
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
` (2 preceding siblings ...)
2022-02-04 11:34 ` [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
@ 2022-02-04 12:16 ` Alexander Lobakin
2022-02-04 15:55 ` Alexander Duyck
2022-02-05 15:20 ` patchwork-bot+netdevbpf
5 siblings, 0 replies; 9+ messages in thread
From: Alexander Lobakin @ 2022-02-04 12:16 UTC (permalink / raw)
To: Paolo Abeni
Cc: Alexander Lobakin, netdev, David S. Miller, Jakub Kicinski,
Eric Dumazet, Alexander H Duyck
From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 4 Feb 2022 12:28:35 +0100
> This series collects a couple of small optimizations for the GRO engine,
> reducing slightly the number of cycles for dev_gro_receive().
> The delta is within noise range in tput tests, but with big TCP coming
> every cycle saved from the GRO engine will count - I hope ;)
>
> v1 -> v2:
> - a few cleanup suggested from Alexander(s)
> - moved away the more controversial 3rd patch
>
> Paolo Abeni (2):
> net: gro: avoid re-computing truesize twice on recycle
> net: gro: minor optimization for dev_gro_receive()
Looks nice to me now, thanks!
For the series:
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
>
> include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
> net/core/gro.c | 16 ++++-----------
> 2 files changed, 32 insertions(+), 36 deletions(-)
>
> --
> 2.34.1
Al
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 0/2] gro: a couple of minor optimization
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
` (3 preceding siblings ...)
2022-02-04 12:16 ` Alexander Lobakin
@ 2022-02-04 15:55 ` Alexander Duyck
2022-02-05 15:20 ` patchwork-bot+netdevbpf
5 siblings, 0 replies; 9+ messages in thread
From: Alexander Duyck @ 2022-02-04 15:55 UTC (permalink / raw)
To: Paolo Abeni
Cc: Netdev, David S. Miller, Jakub Kicinski, Alexander Lobakin, Eric Dumazet
On Fri, Feb 4, 2022 at 3:29 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> This series collects a couple of small optimizations for the GRO engine,
> reducing slightly the number of cycles for dev_gro_receive().
> The delta is within noise range in tput tests, but with big TCP coming
> every cycle saved from the GRO engine will count - I hope ;)
>
> v1 -> v2:
> - a few cleanup suggested from Alexander(s)
> - moved away the more controversial 3rd patch
>
> Paolo Abeni (2):
> net: gro: avoid re-computing truesize twice on recycle
> net: gro: minor optimization for dev_gro_receive()
>
> include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
> net/core/gro.c | 16 ++++-----------
> 2 files changed, 32 insertions(+), 36 deletions(-)
This addresses the concern I had.
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle
2022-02-04 11:28 ` [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle Paolo Abeni
@ 2022-02-04 16:34 ` Eric Dumazet
0 siblings, 0 replies; 9+ messages in thread
From: Eric Dumazet @ 2022-02-04 16:34 UTC (permalink / raw)
To: Paolo Abeni
Cc: netdev, David S. Miller, Jakub Kicinski, Alexander Lobakin,
Alexander H Duyck
On Fri, Feb 4, 2022 at 3:29 AM Paolo Abeni <pabeni@redhat.com> wrote:
>
> After commit 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb
> carring sock reference") and commit af352460b465 ("net: fix GRO
> skb truesize update") the truesize of the skb with stolen head is
> properly updated by the GRO engine, we don't need anymore resetting
> it at recycle time.
>
> v1 -> v2:
> - clarify the commit message (Alexander)
>
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> ---
Reviewed-by: Eric Dumazet <edumazet@google.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 0/2] gro: a couple of minor optimization
2022-02-04 11:34 ` [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
@ 2022-02-05 9:51 ` David Miller
0 siblings, 0 replies; 9+ messages in thread
From: David Miller @ 2022-02-05 9:51 UTC (permalink / raw)
To: pabeni; +Cc: netdev, kuba, alexandr.lobakin, edumazet, alexander.duyck
From: Paolo Abeni <pabeni@redhat.com>
Date: Fri, 04 Feb 2022 12:34:03 +0100
> On Fri, 2022-02-04 at 12:28 +0100, Paolo Abeni wrote:
>> This series collects a couple of small optimizations for the GRO engine,
>> reducing slightly the number of cycles for dev_gro_receive().
>> The delta is within noise range in tput tests, but with big TCP coming
>> every cycle saved from the GRO engine will count - I hope ;)
>>
>> v1 -> v2:
>> - a few cleanup suggested from Alexander(s)
>> - moved away the more controversial 3rd patch
>>
>> Paolo Abeni (2):
>> net: gro: avoid re-computing truesize twice on recycle
>> net: gro: minor optimization for dev_gro_receive()
>>
>> include/net/gro.h | 52 +++++++++++++++++++++++++----------------------
>> net/core/gro.c | 16 ++++-----------
>> 2 files changed, 32 insertions(+), 36 deletions(-)
>
> This is really a v2. Please let me know if you prefer a formal repost.
Not necessary.
Thank you.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH net-next 0/2] gro: a couple of minor optimization
2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
` (4 preceding siblings ...)
2022-02-04 15:55 ` Alexander Duyck
@ 2022-02-05 15:20 ` patchwork-bot+netdevbpf
5 siblings, 0 replies; 9+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-02-05 15:20 UTC (permalink / raw)
To: Paolo Abeni
Cc: netdev, davem, kuba, alexandr.lobakin, edumazet, alexander.duyck
Hello:
This series was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:
On Fri, 4 Feb 2022 12:28:35 +0100 you wrote:
> This series collects a couple of small optimizations for the GRO engine,
> reducing slightly the number of cycles for dev_gro_receive().
> The delta is within noise range in tput tests, but with big TCP coming
> every cycle saved from the GRO engine will count - I hope ;)
>
> v1 -> v2:
> - a few cleanup suggested from Alexander(s)
> - moved away the more controversial 3rd patch
>
> [...]
Here is the summary with links:
- [net-next,1/2] net: gro: avoid re-computing truesize twice on recycle
https://git.kernel.org/netdev/net-next/c/7881453e4adf
- [net-next,2/2] net: gro: minor optimization for dev_gro_receive()
https://git.kernel.org/netdev/net-next/c/de5a1f3ce4c8
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 9+ messages in thread
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2022-02-04 11:28 [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
2022-02-04 11:28 ` [PATCH net-next 1/2] net: gro: avoid re-computing truesize twice on recycle Paolo Abeni
2022-02-04 16:34 ` Eric Dumazet
2022-02-04 11:28 ` [PATCH net-next 2/2] net: gro: minor optimization for dev_gro_receive() Paolo Abeni
2022-02-04 11:34 ` [PATCH net-next 0/2] gro: a couple of minor optimization Paolo Abeni
2022-02-05 9:51 ` David Miller
2022-02-04 12:16 ` Alexander Lobakin
2022-02-04 15:55 ` Alexander Duyck
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