commit d916701c670701e1ab4d0ed3d4e64d6023bccec9
author Giuseppe CAVALLARO <peppe.cavallaro@st.com> Mon Mar 10 13:40:32 2014 +0100
committer David S. Miller <davem@davemloft.net> Tue Mar 11 16:14:31 2014 -0400
tree f4ecc52fa4f6d75af2d0cc5e95e975784633f0cc
parent 83bf79b6bb64e686ccf0b66b6828b7bfe9f70ae9

stmmac: fix and better tune the default buffer sizes

This patch is to fix and tune the default buffer sizes.
It reduces the default bufsize used by the driver from
4KiB to 1536 bytes.

Patch has been tested on both ARM and SH4 platform based.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index b418f94..5365836 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -92,8 +92,8 @@
 module_param(tc, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(tc, "DMA threshold control value");
 
-#define DMA_BUFFER_SIZE	BUF_SIZE_4KiB
-static int buf_sz = DMA_BUFFER_SIZE;
+#define	DEFAULT_BUFSIZE	1536
+static int buf_sz = DEFAULT_BUFSIZE;
 module_param(buf_sz, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(buf_sz, "DMA buffer size");
 
@@ -136,8 +136,8 @@
 		dma_rxsize = DMA_RX_SIZE;
 	if (unlikely(dma_txsize < 0))
 		dma_txsize = DMA_TX_SIZE;
-	if (unlikely((buf_sz < DMA_BUFFER_SIZE) || (buf_sz > BUF_SIZE_16KiB)))
-		buf_sz = DMA_BUFFER_SIZE;
+	if (unlikely((buf_sz < DEFAULT_BUFSIZE) || (buf_sz > BUF_SIZE_16KiB)))
+		buf_sz = DEFAULT_BUFSIZE;
 	if (unlikely(flow_ctrl > 1))
 		flow_ctrl = FLOW_AUTO;
 	else if (likely(flow_ctrl < 0))
@@ -901,10 +901,10 @@
 		ret = BUF_SIZE_8KiB;
 	else if (mtu >= BUF_SIZE_2KiB)
 		ret = BUF_SIZE_4KiB;
-	else if (mtu >= DMA_BUFFER_SIZE)
+	else if (mtu > DEFAULT_BUFSIZE)
 		ret = BUF_SIZE_2KiB;
 	else
-		ret = DMA_BUFFER_SIZE;
+		ret = DEFAULT_BUFSIZE;
 
 	return ret;
 }