From 344fa462e3246bd102059ccc3c59deef416676dd Mon Sep 17 00:00:00 2001
From: Lars Ellenberg <lars.ellenberg@linbit.com>
Date: Tue, 25 May 2010 14:23:57 +0200
Subject: [PATCH] drbd: improve network latency, TCP_QUICKACK
On Thu, Apr 29, 2010 at 04:00:50PM -0400, Eduard.Guzovsky@stratus.com
wrote on drbd-dev@lists.linbit.com
Subject: [Drbd-dev] DRBD small synchronous writes performance improvements
> 1. TCP_QUICKACK option is set incorrectly. The goal was force TCP to
> send and ACK as a "one time" event. Instead the code permanently sets
> connection in the QUICKACK mode.
He is right, we actually want to use an even val with TCP_QUICKACK.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
---
drivers/block/drbd/drbd_int.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index c194348a46ed..6d79a76ba597 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1540,7 +1540,7 @@ static inline void drbd_tcp_nodelay(struct socket *sock)
static inline void drbd_tcp_quickack(struct socket *sock)
{
- int __user val = 1;
+ int __user val = 2;
(void) drbd_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
(char __user *)&val, sizeof(val));
}