From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH 4/6] sky2: reduce default Tx ring size Date: Wed, 16 Nov 2011 15:42:58 -0800 Message-ID: <20111116234344.813201788@vyatta.com> References: <20111116234254.319625694@vyatta.com> Cc: netdev@vger.kernel.org To: davem@davemloft.net Return-path: Received: from sfca-50.vyatta.com ([76.74.103.50]:48427 "EHLO fiji.vyatta.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754158Ab1KPXwd (ORCPT ); Wed, 16 Nov 2011 18:52:33 -0500 Content-Disposition: inline; filename=sky2-tx-debloat.patch Sender: netdev-owner@vger.kernel.org List-ID: The default Tx ring size for the sky2 driver is quite large and could cause excess buffer bloat for many users. The minimum ring size possible and still allow handling the worst case packet on 64bit platforms is 38 which gets rounded up to a power of 2. But most packets only require a couple of ring elements. Signed-off-by: Stephen Hemminger --- a/drivers/net/ethernet/marvell/sky2.c 2011-11-16 15:19:39.518659262 -0800 +++ b/drivers/net/ethernet/marvell/sky2.c 2011-11-16 15:19:40.990692544 -0800 @@ -68,7 +68,7 @@ #define MAX_SKB_TX_LE (2 + (sizeof(dma_addr_t)/sizeof(u32))*(MAX_SKB_FRAGS+1)) #define TX_MIN_PENDING (MAX_SKB_TX_LE+1) #define TX_MAX_PENDING 1024 -#define TX_DEF_PENDING 127 +#define TX_DEF_PENDING 63 #define TX_WATCHDOG (5 * HZ) #define NAPI_WEIGHT 64