Hi Peter, This was a very insightful answer for me! Thx for sharing all your learnings!!
Op zo 18 sep. 2022 om 21:11 schreef Peter <pe...@peter2000.co.uk>: > I will be amazed if you find anybody who knows what most of the > options in the lwipopts.h file do *and* is willing to post it. LWIP is > a typical open source piece of code, unsupported and those who > developed it have moved on to more interesting things many years ago. > So the web is full of desperate people posting everywhere asking > questions like this. > > I have spent a chunk of my life this year messing about with this > stuff. LWIP does actually work very well, which is just as well > considering the above! > > One thing I found is that the buffer config makes practically no > difference to performance in a typical embedded system (i.e. not a > 3GHz PC CPU!). So I was able to achieve a big reduction in the memory > usage. > > Below is my lwipopts.h file with comments which I believe to be > correct. > > /** > > > ****************************************************************************** > * @file LwIP/LwIP_HTTP_Server_Netconn_RTOS/Inc/lwipopts.h > * @author MCD Application Team > * @brief lwIP Options Configuration. > > > ****************************************************************************** > * > * This sort of explains the memory usage > * https://lwip-users.nongnu.narkive.com/dkzkPa8l/lwip-memory-settings > * https://www.cnblogs.com/shangdawei/p/3494148.html > * https://lwip.fandom.com/wiki/Tuning_TCP > * https://groups.google.com/g/osdeve_mirror_tcpip_lwip/c/lFYJ7Fw0Cxg > * ST UM1713 document gives an overview of integrating all this. > * > * > * > * > * 7/7/22 PH MEM_SIZE set to 5k (was 10k). Only ~1.5k is > used. > * 13/7/22 PH MEMP_MEM_MALLOC=1, MEM_SIZE=16k. > * 14/7/22 PH MEMP_MEM_MALLOC=0; 1 was unreliable. 8 x 512 > byte buffers now. > * 6/8/22 PH 4 x MTU buffers for RX. Done partly for > EditGetData(). > * MEM_SIZE=6k. 5k is used - see .map > file for ram_heap address. > * Sizes of various static RAM structures > determined experimentally. > * > * > * > * > * > * > * > */ > #ifndef __LWIPOPTS_H__ > #define __LWIPOPTS_H__ > > /** > * NO_SYS==1: Provides VERY minimal functionality. Otherwise, > * use lwIP facilities. > */ > #define NO_SYS 0 > > // Flag to make LWIP API thread-safe. The netconn and socket APIs are > claimed > // to be thread-safe anyway. The raw API is never thread-safe. > #define LWIP_TCPIP_CORE_LOCKING 1 > > // This places more objects into the static block defined by MEM_SIZE. > // Uses mem_malloc/mem_free instead of the lwip pool allocator. > // MEM_SIZE now needs to be increased by about 10k. > // It doesn't magically produce extra memory, and causes crashes. > // There is also a performance loss, apparently. AVOID. > #define MEMP_MEM_MALLOC 0 > > > //NC: Need for sending PING messages by keepalive > #define LWIP_RAW 1 > #define DEFAULT_RAW_RECVMBOX_SIZE 4 > > > /*-----------------------------------------------------------------------------*/ > > /* LwIP Stack Parameters (modified compared to initialization value in > opt.h) -*/ > /* Parameters set in STM32CubeMX LwIP Configuration GUI -*/ > > /*----- Value in opt.h for LWIP_DNS: 0 -----*/ > #define LWIP_DNS 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. This is a statically > allocated block. You can find it > // in the .map file as the symbol ram_heap and you can see how much of > this RAM gets used. > // If MEMP_MEM_MALLOC=0, this holds just the PBUF_ stuff. > // If MEMP_MEM_MALLOC=1 (which is not reliable) this greatly expands > and needs 16k+. > // Empirically this needs to be big enough for at least 4 x > PBUF_POOL_BUFSIZE. > // 6k yields a good speed and going to 8k+ makes a minimal > improvement. The main > // factor affecting speed in the KDE is the poll period in > ethernetif_input(). > // This value also limits the biggest block size sent out by > netconn_write. With the > // MEM_SIZE of 6k, the biggest block netconn_write will send out is > 4k. > #define MEM_SIZE (6*1024) > > // MEMP_ structures. Their sizes have been determined experimentally, > by > // increasing them and seeing free RAM changing. > > /* 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 5 // each 1 is 20 bytes of > static RAM > > /* MEMP_NUM_UDP_PCB: the number of UDP protocol control blocks. One > per active UDP "connection". */ > #define MEMP_NUM_UDP_PCB 6 // each 1 is 32 bytes of > static RAM > > /* MEMP_NUM_TCP_PCB: the number of simultaneously active TCP > connections. */ > #define MEMP_NUM_TCP_PCB 5 // each 1 is 145 bytes of > static RAM > > /* MEMP_NUM_TCP_PCB_LISTEN: the number of listening TCP > connections. */ > #define MEMP_NUM_TCP_PCB_LISTEN 5 // each 1 is 28 bytes of > static RAM > > /* MEMP_NUM_TCP_SEG: the number of simultaneously queued TCP > segments. */ > #define MEMP_NUM_TCP_SEG 8 // each 1 is 20 bytes of > static RAM > > /* MEMP_NUM_SYS_TIMEOUT: the number of simulateously active > timeouts. */ > #define MEMP_NUM_SYS_TIMEOUT 10 // each 1 is 16 bytes of > static RAM > > > /* ---------- Pbuf dynamically allocated buffer blocks ---------- */ > > // These settings are probably for RECEIVE only and make negligible > difference > // to performance, which is dominated by the low_level_input poll > period. These > // PBUFs relate directly to the netconn API netbufs etc. > > /* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */ > // Statically allocated, so setting this to 2 frees up another 3k of > RAM > #define PBUF_POOL_SIZE 4 > > /* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. */ > // ** It is better to use 4 x MTU than 8 x 512 because in say > EditGetData() you are ** > // ** much more likely to get the whole file header in the first > packet. With 512 ** > // ** byte packets the CRLFCRLF marker is only ~64 bytes before the > end of the pkt ** > // ** Same issue in UploadGetData where we need to get the whole > header in. ** > #define PBUF_POOL_BUFSIZE 1500 + PBUF_LINK_ENCAPSULATION_HLEN + > PBUF_LINK_HLEN + PBUF_IP_HLEN + PBUF_TRANSPORT_HLEN > > /* --------------------------------------------------------------- */ > > > /* ---------- TCP options ---------- */ > #define LWIP_TCP 1 > #define TCP_TTL 255 > > /* 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 0 > > /* TCP Maximum segment size. */ > #define TCP_MSS (1500 - 40) /* TCP_MSS = > (Ethernet MTU - IP header size - TCP header size) */ > > /* TCP sender buffer space (bytes). */ > #define TCP_SND_BUF (4*TCP_MSS) // no effect > on static RAM > > /* TCP_SND_QUEUELEN: TCP sender buffer space (pbufs). This must be at > least > as much as (2 * TCP_SND_BUF/TCP_MSS) for things to work. */ > > #define TCP_SND_QUEUELEN (2* TCP_SND_BUF/TCP_MSS) > > /* TCP advertised receive window. */ > // Should be less than PBUF_POOL_SIZE * (PBUF_POOL_BUFSIZE - protocol > headers) > #define TCP_WND (2*TCP_MSS) // no effect > on static RAM > > > /* ---------- ICMP options ---------- */ > #define LWIP_ICMP 1 > > > /* ---------- DHCP options ---------- */ > #define LWIP_DHCP 1 > > > /* ---------- UDP options ---------- */ > #define LWIP_UDP 1 > #define UDP_TTL 255 > > > /* ---------- Statistics options ---------- */ > #define LWIP_STATS 0 > > /* ---------- link callback options ---------- */ > /* LWIP_NETIF_LINK_CALLBACK==1: Support a callback function from an > interface > * whenever the link changes (i.e., link down) > * 8/2022 this is done from the low_level_input RTOS task. > */ > #define LWIP_NETIF_LINK_CALLBACK 0 > > > > > /* > -------------------------------------- > ---------- Checksum options ---------- > -------------------------------------- > */ > > /* > The STM32F4xx allows computing and verifying the IP, UDP, TCP and ICMP > checksums by hardware: > - To use this feature let the following define uncommented. > - To disable it and process by CPU comment the the checksum. > */ > #define CHECKSUM_BY_HARDWARE > > > #ifdef CHECKSUM_BY_HARDWARE > /* CHECKSUM_GEN_IP==0: Generate checksums by hardware for outgoing > IP packets.*/ > #define CHECKSUM_GEN_IP 0 > /* CHECKSUM_GEN_UDP==0: Generate checksums by hardware for outgoing > UDP packets.*/ > #define CHECKSUM_GEN_UDP 0 > /* CHECKSUM_GEN_TCP==0: Generate checksums by hardware for outgoing > TCP packets.*/ > #define CHECKSUM_GEN_TCP 0 > /* CHECKSUM_CHECK_IP==0: Check checksums by hardware for incoming IP > packets.*/ > #define CHECKSUM_CHECK_IP 0 > /* CHECKSUM_CHECK_UDP==0: Check checksums by hardware for incoming > UDP packets.*/ > #define CHECKSUM_CHECK_UDP 0 > /* CHECKSUM_CHECK_TCP==0: Check checksums by hardware for incoming > TCP packets.*/ > #define CHECKSUM_CHECK_TCP 0 > /* CHECKSUM_CHECK_ICMP==0: Check checksums by hardware for incoming > ICMP packets.*/ > #define CHECKSUM_GEN_ICMP 0 > #else > /* CHECKSUM_GEN_IP==1: Generate checksums in software for outgoing > IP packets.*/ > #define CHECKSUM_GEN_IP 1 > /* CHECKSUM_GEN_UDP==1: Generate checksums in software for outgoing > UDP packets.*/ > #define CHECKSUM_GEN_UDP 1 > /* CHECKSUM_GEN_TCP==1: Generate checksums in software for outgoing > TCP packets.*/ > #define CHECKSUM_GEN_TCP 1 > /* CHECKSUM_CHECK_IP==1: Check checksums in software for incoming IP > packets.*/ > #define CHECKSUM_CHECK_IP 1 > /* CHECKSUM_CHECK_UDP==1: Check checksums in software for incoming > UDP packets.*/ > #define CHECKSUM_CHECK_UDP 1 > /* CHECKSUM_CHECK_TCP==1: Check checksums in software for incoming > TCP packets.*/ > #define CHECKSUM_CHECK_TCP 1 > /* CHECKSUM_CHECK_ICMP==1: Check checksums by hardware for incoming > ICMP packets.*/ > #define CHECKSUM_GEN_ICMP 1 > #endif > > > /* > ---------------------------------------------- > ---------- Sequential layer options ---------- > ---------------------------------------------- > */ > /** > * LWIP_NETCONN==1: Enable Netconn API (require to use api_lib.c) > */ > #define LWIP_NETCONN 1 > > /* > ------------------------------------ > ---------- Socket options ---------- > ------------------------------------ > */ > /** > * LWIP_SOCKET==1: Enable Socket API (require to use sockets.c) > */ > #define LWIP_SOCKET 1 > > /* > ------------------------------------ > ---------- httpd options ---------- > ------------------------------------ > */ > /** Set this to 1 to include "fsdata_custom.c" instead of "fsdata.c" > for the > * file system (to prevent changing the file included in CVS) */ > #define HTTPD_USE_CUSTOM_FSDATA 0 > > /* > --------------------------------- > ---------- OS options ---------- > --------------------------------- > */ > > #define TCPIP_THREAD_NAME "TCP/IP" > #define TCPIP_THREAD_STACKSIZE 4096 > #define TCPIP_MBOX_SIZE 6 > #define DEFAULT_UDP_RECVMBOX_SIZE 6 > #define DEFAULT_TCP_RECVMBOX_SIZE 6 > #define DEFAULT_ACCEPTMBOX_SIZE 6 > #define DEFAULT_THREAD_STACKSIZE 512 > #define TCPIP_THREAD_PRIO osPriorityHigh > > #define LWIP_DEBUG 1 > > #define IP_DEBUG LWIP_DBG_ON > #define DHCP_DEBUG LWIP_DBG_OFF > #define UDP_DEBUG LWIP_DBG_ON > #define SOCKET_DEBUG_LWIP_DBG_ON > //#define ICMP_DEBUG LWIP_DBG_ON|LWIP_DBG_TRACE > //#define NETIF_DEBUG LWIP_DBG_OFF > #define LWIP_DBG_TYPES_ON (LWIP_DBG_TRACE|LWIP_DBG_STATE) > #define LWIP_SO_RCVTIMEO 1 > #define LWIP_NETIF_HOSTNAME 1 > > #define SO_REUSE 1 > > // Defining these produces various errors > //#define LWIP_IPV6 1 > //#define LWIP_IPV6_DHCP6 1 > > #endif /* __LWIPOPTS_H__ */ > > _______________________________________________ > lwip-users mailing list > lwip-users@nongnu.org > https://lists.nongnu.org/mailman/listinfo/lwip-users >
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