Jens,
here's the other patch I was talking about, for better behaviour of

non-blocking splice(). Ben Mansell also confirms similar improvements

in his tests, where non-blocking splice() initially showed half of

read()/write() performance. Ben, would you mind adding a Tested-By

line ?
Also, please note that this is unrelated to the corruption bug I reported

and does not fix it.
Regards,

Willy
From fafe76713523c8e9767805cfdc7b73323d7bf180 Mon Sep 17 00:00:00 2001

From: Willy Tarreau

Date: Thu, 8 Jan 2009 17:10:13 +0100

Subject: [PATCH] tcp: splice as many packets as possible at once
Currently, in non-blocking mode, tcp_splice_read() returns after

splicing one segment regardless of the len argument. This results

in low performance and very high overhead due to syscall rate when

splicing from interfaces which do not support LRO.
The fix simply consists in not breaking out of the loop after the

first read. That way, we can read up to the size requested by the

caller and still return when there is no data left.
Performance has significantly improved with this fix, with the

number of calls to splice() divided by about 20, and CPU usage

dropped from 100% to 75%.
Signed-off-by: Willy Tarreau

---

 net/ipv4/tcp.c |    2 +-

 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c

index 35bcddf..80261b4 100644

--- a/net/ipv4/tcp.c

+++ b/net/ipv4/tcp.c

@@ -615,7 +615,7 @@ ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,

 		lock_sock(sk);
 		if (sk->sk_err || sk->sk_state == TCP_CLOSE ||

-		    (sk->sk_shutdown & RCV_SHUTDOWN) || !timeo ||

+		    (sk->sk_shutdown & RCV_SHUTDOWN) ||

 		    signal_pending(current))

 			break;

 	}

--

1.6.0.3
--

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