Hi Kieran,I may have to take back my accusation regarding "Requiring ACK for every two TCP packets "
Please see attachment smallerpacket_retransmit.pcap, it sends out three packets. So the problem may be in the tx buffer size.
Also attached is lwipopts.h, and I checked a few times, and believed I specify a decent tx buffer.
/* TCP sender buffer space (bytes). */ #define TCP_SND_BUF 30000Maybe you can point out my mistake in the setting, or maybe there is an error in lwip that ignores such setting.
Thanks again for your time and help! Regards, Chen >>>>>>>>>>>>>>>>>>> Hi Kieran,NonAVR retransmit after a specified amount of timeout (RTO) or transmit pool is near full. The reason you don't see any retransmission is because the time-out was set very high on purpose.
Requiring ACK for every two TCP packets is not good for high-speed communication:
Since the ACK can take a long time to come back if the final product is deployed over the internet. For example, if it takes 0.5 seconds for ACK to come back, which is shorter than RTO, then the maximum data rate is 2*1460*2, where the first 2 represents the two packets before the ACK, 1460 is the max payload, and the second 2 is max ACK within a second, and the result is only merely 5.8KB/sec
Could you reconsider my request? (not necessary the same as NonAVR, but something better than the current lwip)
Thanks! Chen
On Fri, 2010-12-10 at 15:50 -0500, Chen wrote: > > Both cases were created by pulling the ethernet cable on the PC to > demonstrate the retransmit mechanism, and Nagel is disabled in both > cases. > > *** THERE IS NOTHING WRONG IN LWIP'S APPROACH ***, but there is room > to improve: If the ack comes in slower than usual, the Non-lwip > approach will keep the flow going and have no impact on the throughput > rate. > > May I request such option in the future lwip? I really don't like the NonAVR version. What will cause it to start retransmission? It seems to have ignored the TCP retransmission timeout and is just carrying on sending new data regardless. I would be against any change to make lwIP behave more like this. I'm happy to see it carry on sending data until the RTO fires, but after that we must assume something is wrong and stop sending new data to retransmit old packets. Kieran
smallerpacket_retransmit.pcap
Description: Binary data
/* This header file is part of the ATMEL AVR32-SoftwareFramework-AT32UC3A-1.4.0 Release */ /*This file has been prepared for Doxygen automatic documentation generation.*/ /*! \file ********************************************************************* * * \brief lwIP configuration for AVR32 UC3. * * - Compiler: GNU GCC for AVR32 * - Supported devices: All AVR32 devices can be used. * - AppNote: * * \author Atmel Corporation: http://www.atmel.com \n * Support and FAQ: http://support.atmel.no/ * *****************************************************************************/ /* Copyright (C) 2006-2008, Atmel Corporation All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * 1. Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * 3. The name of ATMEL may not be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY ATMEL ``AS IS'' AND ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND * SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef __LWIPOPTS_H__ #define __LWIPOPTS_H__ /* Include user defined options first */ // #include "conf_eth.h" #include "conf_lwip_threads.h" //#define LWIP_NOASSERT 1 // To suppress some errors for now (no debug output) #include "lwip/debug.h" /* Define default values for unconfigured parameters. */ /* These two control is reclaimer functions should be compiled in. Should always be turned on (1). */ #define MEM_RECLAIM 1 #define MEMP_RECLAIM 1 /* Platform specific locking */ /* * enable SYS_LIGHTWEIGHT_PROT in lwipopts.h if you want inter-task protection * for certain critical regions during buffer allocation, deallocation and memory * allocation and deallocation. */ #define SYS_LIGHTWEIGHT_PROT 1 /* ---------- Memory options ---------- */ /* MEM_ALIGNMENT: should be set to the alignment of the CPU for which lwIP is compiled. 4 byte alignment -> define MEM_ALIGNMENT to 4, 2 byte alignment -> define MEM_ALIGNMENT to 2. */ #define MEM_ALIGNMENT 4 /* MEM_SIZE: the size of the heap memory. If the application will send a lot of data that needs to be copied, this should be set high. */ #define MEM_SIZE 10 * 1024 /* MEMP_NUM_PBUF: the number of memp struct pbufs. If the application sends a lot of data out of ROM (or other static memory), this should be set high. */ #define MEMP_NUM_PBUF 6 /* Number of raw connection PCBs */ #define MEMP_NUM_RAW_PCB 1 #if (TFTP_USED == 1) /* ---------- UDP options ---------- */ #define LWIP_UDP 1 #define UDP_TTL 255 /* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One per active UDP "connection". */ #define MEMP_NUM_UDP_PCB 3 #else /* ---------- UDP options ---------- */ #define LWIP_UDP 1 #define UDP_TTL 0 /* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One per active UDP "connection". */ #define MEMP_NUM_UDP_PCB 0 #endif /* MEMP_NUM_TCP_PCB: the number of simultaneously active TCP connections. */ #define MEMP_NUM_TCP_PCB 2 /* MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP connections. */ #define MEMP_NUM_TCP_PCB_LISTEN 1 /* MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP segments. */ #define MEMP_NUM_TCP_SEG 9 /* MEMP_NUM_SYS_TIMEOUT: the number of simulateously active timeouts. */ #define MEMP_NUM_SYS_TIMEOUT 6 /* The following four are used only with the sequential API and can be set to 0 if the application only will use the raw API. */ /* MEMP_NUM_NETBUF: the number of struct netbufs. */ #define MEMP_NUM_NETBUF 3 /* MEMP_NUM_NETCONN: the number of struct netconns. */ #define MEMP_NUM_NETCONN 4 /* ---------- Pbuf options ---------- */ /* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */ #define PBUF_POOL_SIZE 30 /* TCP sender buffer space (bytes). */ #define TCP_SND_BUF 30000 /* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. */ #define PBUF_POOL_BUFSIZE 500 /* PBUF_LINK_HLEN: the number of bytes that should be allocated for a link level header. */ #define PBUF_LINK_HLEN 16 /* ---------- TCP options ---------- */ #define LWIP_TCP 1 #define LWIP_TCP_KEEPALIVE 1 #define TCP_TTL 255 /* TCP receive window. */ #define TCP_WND 1500 /* Controls if TCP should queue segments that arrive out of order. Define to 0 if your device is low on memory. */ #define TCP_QUEUE_OOSEQ 1 /* TCP Maximum segment size. */ //#define TCP_MSS 1500 #define TCP_MSS 1460 /* TCP sender buffer space (pbufs). This must be at least = 2 * TCP_SND_BUF/TCP_MSS for things to work. */ #define TCP_SND_QUEUELEN 6 * TCP_SND_BUF/TCP_MSS /* Maximum number of retransmissions of data segments. */ #define TCP_MAXRTX 12 /* Maximum number of retransmissions of SYN segments. */ #define TCP_SYNMAXRTX 4 /** * DEFAULT_RAW_RECVMBOX_SIZE: The mailbox size for the incoming packets on a * NETCONN_RAW. The queue size value itself is platform-dependent, but is passed * to sys_mbox_new() when the recvmbox is created. */ #define DEFAULT_RAW_RECVMBOX_SIZE 6 /** * DEFAULT_UDP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a * NETCONN_UDP. The queue size value itself is platform-dependent, but is passed * to sys_mbox_new() when the recvmbox is created. */ #define DEFAULT_UDP_RECVMBOX_SIZE 6 /** * DEFAULT_TCP_RECVMBOX_SIZE: The mailbox size for the incoming packets on a * NETCONN_TCP. The queue size value itself is platform-dependent, but is passed * to sys_mbox_new() when the recvmbox is created. */ #define DEFAULT_TCP_RECVMBOX_SIZE 6 /** * DEFAULT_ACCEPTMBOX_SIZE: The mailbox size for the incoming connections. * The queue size value itself is platform-dependent, but is passed to * sys_mbox_new() when the acceptmbox is created. */ #define DEFAULT_ACCEPTMBOX_SIZE 6 /* ---------- ARP options ---------- */ #define ARP_TABLE_SIZE 10 #define ARP_QUEUEING 0 /* ---------- IP options ---------- */ /* Define IP_FORWARD to 1 if you wish to have the ability to forward IP packets across network interfaces. If you are going to run lwIP on a device with only one network interface, define this to 0. */ #define IP_FORWARD 0 /* If defined to 1, IP options are allowed (but not parsed). If defined to 0, all packets with IP options are dropped. */ #define IP_OPTIONS 1 /* ---------- ICMP options ---------- */ #define ICMP_TTL 255 /* ---------- DHCP options ---------- */ /* Define LWIP_DHCP to 1 if you want DHCP configuration of interfaces. DHCP is not implemented in lwIP 0.5.1, however, so turning this on does currently not work. */ #define LWIP_DHCP 1 #define LWIP_AUTOIP 1 #define LWIP_DHCP_AUTOIP_COOP 1 /* 1 if you want to do an ARP check on the offered address (recommended). */ //#define DHCP_DOES_ARP_CHECK 1 /* ------------------------------------ ---------- Thread options ---------- ------------------------------------ */ /** * TCPIP_THREAD_NAME: The name assigned to the main tcpip thread. */ #define TCPIP_THREAD_NAME "TCP/IP" /** * TCPIP_THREAD_STACKSIZE: The stack size used by the main tcpip thread. * The stack size value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define TCPIP_THREAD_STACKSIZE lwipINTERFACE_STACK_SIZE /** * TCPIP_THREAD_PRIO: The priority assigned to the main tcpip thread. * The priority value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define TCPIP_THREAD_PRIO lwipINTERFACE_TASK_PRIORITY /** * TCPIP_MBOX_SIZE: The mailbox size for the tcpip thread messages * The queue size value itself is platform-dependent, but is passed to * sys_mbox_new() when tcpip_init is called. */ #define TCPIP_MBOX_SIZE 6 /** * SLIPIF_THREAD_NAME: The name assigned to the slipif_loop thread. */ #define SLIPIF_THREAD_NAME "slipif" /** * SLIP_THREAD_STACKSIZE: The stack size used by the slipif_loop thread. * The stack size value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define SLIPIF_THREAD_STACKSIZE configMINIMAL_STACK_SIZE /** * SLIPIF_THREAD_PRIO: The priority assigned to the slipif_loop thread. * The priority value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define SLIPIF_THREAD_PRIO 1 /** * PPP_THREAD_NAME: The name assigned to the pppMain thread. */ #define PPP_THREAD_NAME "pppMain" /** * PPP_THREAD_STACKSIZE: The stack size used by the pppMain thread. * The stack size value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define PPP_THREAD_STACKSIZE configMINIMAL_STACK_SIZE /** * PPP_THREAD_PRIO: The priority assigned to the pppMain thread. * The priority value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define PPP_THREAD_PRIO 1 /** * DEFAULT_THREAD_NAME: The name assigned to any other lwIP thread. */ #define DEFAULT_THREAD_NAME "lwIP" /** * DEFAULT_THREAD_STACKSIZE: The stack size used by any other lwIP thread. * The stack size value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define DEFAULT_THREAD_STACKSIZE configMINIMAL_STACK_SIZE /** * DEFAULT_THREAD_PRIO: The priority assigned to any other lwIP thread. * The priority value itself is platform-dependent, but is passed to * sys_thread_new() when the thread is created. */ #define DEFAULT_THREAD_PRIO 1 /* ---------- Statistics options ---------- */ #define LWIP_STATS 1 #define LWIP_STATS_DISPLAY 1 #if LWIP_STATS #define LINK_STATS 1 #define IP_STATS 1 #define ICMP_STATS 1 #define UDP_STATS 1 #define TCP_STATS 1 #define MEM_STATS 1 #define MEMP_STATS 1 #define PBUF_STATS 1 #define SYS_STATS 1 #endif /* STATS */ /* ---------- Lwip Debug options ---------- */ //#undef LWIP_DEBUG #define LWIP_DEBUG #define DBG_TYPES_ON 0xff #define ETHARP_DEBUG DBG_OFF #define NETIF_DEBUG DBG_OFF #define PBUF_DEBUG DBG_ON #define API_LIB_DEBUG DBG_OFF #define API_MSG_DEBUG DBG_ON #define SOCKETS_DEBUG DBG_OFF #define ICMP_DEBUG DBG_OFF #define INET_DEBUG DBG_OFF #define IP_DEBUG DBG_OFF #define IP_REASS_DEBUG DBG_OFF #define RAW_DEBUG DBG_OFF #define MEM_DEBUG DBG_OFF #define MEMP_DEBUG DBG_OFF #define SYS_DEBUG DBG_OFF #define TCP_DEBUG DBG_ON #define TCP_INPUT_DEBUG DBG_OFF #define TCP_FR_DEBUG DBG_OFF #define TCP_RTO_DEBUG DBG_OFF #define TCP_CWND_DEBUG DBG_OFF #define TCP_WND_DEBUG DBG_OFF #define TCP_OUTPUT_DEBUG DBG_OFF #define TCP_RST_DEBUG DBG_OFF #define TCP_QLEN_DEBUG DBG_OFF #define UDP_DEBUG DBG_OFF #define TCPIP_DEBUG DBG_OFF #define DBG_MIN_LEVEL LWIP_DBG_LEVEL_SEVERE #endif /* __LWIPOPTS_H__ */
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