All: I use LWIP 1.3.2, after server receive a lot of data packet from client for a while . The system performance is lower, anyone know how to perfact it ?
Vincent Cui Software Engineer Leader Mobile: +8613255150315 Tel: +86 21 34612525x6104 Fax: +86 21 34619770 E-Mail: [email protected]<mailto:[email protected]> Shanghai EnLogic Electric Technology Co., Ltd. Address: 1104-1106, Building A, No.391, Guiping Road, Xuhui District, Shanghai, 200233 From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 2012年4月13日 2:05 To: Mailing list for lwIP users Subject: Re: [lwip-users] tcp_sndbuf return 0 when sending file vincent cui wrote: All I develop a FTP server with lwIP 1.3.2 in Cortex M3 platform, when I use FlashFXP to get file from the server, the tcp_sndbuf always return 0 after work a while . I capture it with wireshark, the file is attached file. The server ip: 192.168.1.51. it seems that transfer error and need retransmission. From the wireshark capture, I cannot see why the segment is retransmitted. Also, at which point do you get tcp_sndbuf==0, and what's the size of tcp_sndbuf initially? I'm afraid that doesn't really help on your problem, though :-( If I were you, I'd first have a look at lwip_stats to see if there are dropped segments or memory (allocation) failures and then monitor the value of tcp_sndbuf() (maybe it keeps getting smaller and never grows again?). My sendcode in server is below: [..] err = tcp_write(pcb, fsd->fifo.buffer + i, (u16_t)(fsd->fifo.size - i), 1); Yikes! Using numbers instead of constants is really a thing people should learn (I'm speaking of TCP_WRITE_FLAG_COPY vs. '1')! We provide the constants for people to use them so we are free to modify what they are defined to. By using '1' instead of TCP_WRITE_FLAG_COPY, you have successfully made your code susceptible to problems with future versions of lwIP (once we decide to change the value of TCP_WRITE_FLAG_COPY) :-) Simon
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