From e76678dd654545c98a5d0bdc66bd41350573c23e Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Sun, 17 May 2009 20:57:47 +0000 Subject: [PATCH] ixgbe: set max desc to prevent total RSC packet size of 64K The performance of hardware RSC is greatly reduced if the total for max rsc descriptors multiplied by the buffer size is greater than 65535. To prevent this we need to adjust the max rsc descriptors appropriately. Signed-off-by: Alexander Duyck Signed-off-by: Jeff Kirsher Signed-off-by: David S. Miller --- drivers/net/ixgbe/ixgbe.h | 2 ++ drivers/net/ixgbe/ixgbe_main.c | 29 ++++++++++++++++++----------- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/net/ixgbe/ixgbe.h b/drivers/net/ixgbe/ixgbe.h index d291d1cbe041..05a24055ac2f 100644 --- a/drivers/net/ixgbe/ixgbe.h +++ b/drivers/net/ixgbe/ixgbe.h @@ -75,6 +75,8 @@ #define IXGBE_RXBUFFER_128 128 /* Used for packet split */ #define IXGBE_RXBUFFER_256 256 /* Used for packet split */ #define IXGBE_RXBUFFER_2048 2048 +#define IXGBE_RXBUFFER_4096 4096 +#define IXGBE_RXBUFFER_8192 8192 #define IXGBE_MAX_RXBUFFER 16384 /* largest size for a single descriptor */ #define IXGBE_RX_HDR_SIZE IXGBE_RXBUFFER_256 diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c index b53f26501173..4ab17ab7fbce 100644 --- a/drivers/net/ixgbe/ixgbe_main.c +++ b/drivers/net/ixgbe/ixgbe_main.c @@ -1995,21 +1995,28 @@ static void ixgbe_configure_rx(struct ixgbe_adapter *adapter) rscctrl = IXGBE_READ_REG(hw, IXGBE_RSCCTL(j)); rscctrl |= IXGBE_RSCCTL_RSCEN; /* - * if packet split is enabled we can only support up - * to max frags + 1 descriptors. + * we must limit the number of descriptors so that the + * total size of max desc * buf_len is not greater + * than 65535 */ - if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) -#if (MAX_SKB_FRAGS < 3) - rscctrl |= IXGBE_RSCCTL_MAXDESC_1; -#elif (MAX_SKB_FRAGS < 7) - rscctrl |= IXGBE_RSCCTL_MAXDESC_4; -#elif (MAX_SKB_FRAGS < 15) + if (adapter->flags & IXGBE_FLAG_RX_PS_ENABLED) { +#if (MAX_SKB_FRAGS > 16) + rscctrl |= IXGBE_RSCCTL_MAXDESC_16; +#elif (MAX_SKB_FRAGS > 8) rscctrl |= IXGBE_RSCCTL_MAXDESC_8; +#elif (MAX_SKB_FRAGS > 4) + rscctrl |= IXGBE_RSCCTL_MAXDESC_4; #else - rscctrl |= IXGBE_RSCCTL_MAXDESC_16; + rscctrl |= IXGBE_RSCCTL_MAXDESC_1; #endif - else - rscctrl |= IXGBE_RSCCTL_MAXDESC_16; + } else { + if (rx_buf_len < IXGBE_RXBUFFER_4096) + rscctrl |= IXGBE_RSCCTL_MAXDESC_16; + else if (rx_buf_len < IXGBE_RXBUFFER_8192) + rscctrl |= IXGBE_RSCCTL_MAXDESC_8; + else + rscctrl |= IXGBE_RSCCTL_MAXDESC_4; + } IXGBE_WRITE_REG(hw, IXGBE_RSCCTL(j), rscctrl); } /* Disable RSC for ACK packets */ -- 2.30.2