From: Herbert Xu <herbert@gondor.apana.org.au>
To: "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org
Subject: [PATCH 7/14] tcp: Optimise len/mss comparison
Date: Wed, 27 May 2009 14:50:26 +1000 [thread overview]
Message-ID: <E1M9B5u-0001SI-Jj@gondolin.me.apana.org.au> (raw)
In-Reply-To: 20090527044539.GA32372@gondor.apana.org.au
tcp: Optimise len/mss comparison
Instead of checking len > mss || len == 0, we can accomplish
both by checking (len - 1) > mss using the unsigned wraparound.
At nearly a million times a second, this might just help.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 313960e..68342d4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2566,7 +2566,7 @@ found:
mss = skb_shinfo(p)->gso_size;
- flush |= (len > mss) | !len;
+ flush |= (len - 1) >= mss;
flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);
if (flush || skb_gro_receive(head, skb)) {
next prev parent reply other threads:[~2009-05-27 4:50 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-27 4:45 [0/14] GRO: Lots of microoptimisations Herbert Xu
2009-05-27 4:50 ` [PATCH 1/14] gro: Open-code frags copy in skb_gro_receive Herbert Xu
2009-05-27 4:50 ` [PATCH 2/14] gro: Inline skb_gro_header and cache frag0 virtual address Herbert Xu
2009-05-27 4:50 ` [PATCH 3/14] gro: Localise offset/headlen in skb_gro_offset Herbert Xu
2009-05-27 4:50 ` [PATCH 4/14] gro: Only use skb_gro_header for completely non-linear packets Herbert Xu
2009-05-27 4:50 ` [PATCH 5/14] tcp: Optimise GRO port comparisons Herbert Xu
2009-05-27 4:50 ` [PATCH 6/14] tcp: Remove unnecessary window comparisons for GRO Herbert Xu
2009-05-27 4:50 ` Herbert Xu [this message]
2009-05-27 4:50 ` [PATCH 8/14] gro: Optimise length comparison in skb_gro_header Herbert Xu
2009-05-27 4:50 ` [PATCH 9/14] gro: Avoid unnecessary comparison after skb_gro_header Herbert Xu
2009-05-27 4:50 ` [PATCH 10/14] ipv4: Use 32-bit loads for ID and length in GRO Herbert Xu
2009-05-27 18:00 ` Andi Kleen
2009-05-27 21:26 ` Herbert Xu
2009-05-27 4:50 ` [PATCH 11/14] gro: Open-code final pskb_may_pull Herbert Xu
2009-05-27 4:50 ` [PATCH 12/14] gro: Nasty optimisations for page frags in skb_gro_receive Herbert Xu
2009-05-27 4:50 ` [PATCH 13/14] gro: Store shinfo in local variable " Herbert Xu
2009-05-27 4:50 ` [PATCH 14/14] tcp: Do not check flush when comparing options for GRO Herbert Xu
2009-05-27 10:42 ` [0/14] GRO: Lots of microoptimisations David Miller
2009-05-27 17:52 ` Benjamin LaHaise
2009-05-27 23:08 ` Herbert Xu
2009-05-28 15:21 ` Benjamin LaHaise
2009-05-29 9:28 ` Herbert Xu
2009-05-29 9:29 ` Herbert Xu
2009-05-29 16:23 ` Benjamin LaHaise
2009-06-10 5:44 ` Herbert Xu
2009-06-12 16:09 ` Benjamin LaHaise
2009-06-12 23:48 ` David Miller
2009-06-16 16:35 ` Benjamin LaHaise
2009-06-16 16:38 ` Herbert Xu
2009-06-17 8:07 ` Herbert Xu
2009-06-17 8:08 ` Herbert Xu
2009-06-17 20:14 ` Rick Jones
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