Measurement shows that on a MPC8xx running at 132MHz, the optimal
limit is 112:
* 114 bytes packets are processed in 147 TB ticks with higher copybreak
* 114 bytes packets are processed in 148 TB ticks with lower copybreak
* 128 bytes packets are processed in 154 TB ticks with higher copybreak
* 128 bytes packets are processed in 148 TB ticks with lower copybreak
* 238 bytes packets are processed in 172 TB ticks with higher copybreak
* 238 bytes packets are processed in 148 TB ticks with lower copybreak
However it might be different on other processors
and/or frequencies. So it is useful to make it configurable.
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c | 8 +++++---
include/linux/fs_enet_pd.h | 1 -
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
index addcae6..b59bbf8 100644
--- a/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
+++ b/drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c
@@ -60,6 +60,10 @@ module_param(fs_enet_debug, int, 0);
MODULE_PARM_DESC(fs_enet_debug,
"Freescale bitmapped debugging message enable value");
+static int rx_copybreak = 240;
+module_param(rx_copybreak, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(rx_copybreak, "Receive copy threshold");
+
#ifdef CONFIG_NET_POLL_CONTROLLER
static void fs_enet_netpoll(struct net_device *dev);
#endif
@@ -84,7 +88,6 @@ static int fs_enet_napi(struct napi_struct *napi, int budget)
{
struct fs_enet_private *fep = container_of(napi, struct
fs_enet_private, napi);
struct net_device *dev = fep->ndev;
- const struct fs_platform_info *fpi = fep->fpi;
cbd_t __iomem *bdp;
struct sk_buff *skb, *skbn;
int received = 0;
@@ -232,7 +235,7 @@ static int fs_enet_napi(struct napi_struct *napi, int
budget)
pkt_len = CBDR_DATLEN(bdp) - 4; /* remove CRC */
fep->stats.rx_bytes += pkt_len + 4;
- if (pkt_len <= fpi->rx_copybreak) {
+ if (pkt_len <= rx_copybreak) {
/* +2 to make IP header L1 cache aligned */
skbn = netdev_alloc_skb(dev, pkt_len + 2);
if (skbn != NULL) {
@@ -905,7 +908,6 @@ static int fs_enet_probe(struct platform_device *ofdev)
fpi->rx_ring = 32;
fpi->tx_ring = 64;
- fpi->rx_copybreak = 240;
fpi->napi_weight = 17;
fpi->phy_node = of_parse_phandle(ofdev->dev.of_node, "phy-handle", 0);
if (!fpi->phy_node && of_phy_is_fixed_link(ofdev->dev.of_node)) {
diff --git a/include/linux/fs_enet_pd.h b/include/linux/fs_enet_pd.h
index 77d783f..376600e 100644
--- a/include/linux/fs_enet_pd.h
+++ b/include/linux/fs_enet_pd.h
@@ -138,7 +138,6 @@ struct fs_platform_info {
int rx_ring, tx_ring; /* number of buffers on rx */
__u8 macaddr[ETH_ALEN]; /* mac address */
- int rx_copybreak; /* limit we copy small frames */
int napi_weight; /* NAPI weight */
int use_rmii; /* use RMII mode */
--
2.1.0
