[lwip-users] Re: [lwip] problems with tcp_segs

[James Roth]

Andrea Olivotto wrote:

>Hi everyone,
>
>I'm having some problems with segs allocation.
>
>I guess (I'm nearly sure) this is the same problem that James Roth experienced 
>some time ago, as he told in 
>a message dated 12/03/2002.
>In these messsages James told about memp #4 as MEMP_TCP_PCB_LISTEN type, I 
>think #4 is MEMP_TCP_SEG.
>
>In tcp_enqueue() line 140, under heavy ingoing traffic, lwip can't allocate 
>segs:
>
    What platform are you using?  Most of my problems where a result of 
some time related bugs in my code, not lwip.  It turns out that 
imprecise timing code in sys_arch can result it lots of oddball 
problems.  To be specific, the pthread_condtimedwait on my system had an 
early timeout bug.  This resulted in some timeout math going negative.

>
>The problem is that memp_alloc(MEMP_TCP_SEG) return NULL.
>As in James's problem, using stats I could see that the maximum segs allocated 
>is 3, available 48, and may 
>errors (and stats.tcp.memerr == stats.memp[MEMP_TCP_SEG].err and many times 
>stats.tcp.memerr == stats.memp
>[MEMP_TCP_SEG].err == stats.tcp.rexmit).
>
>Does anyone can help me?
>
    We need some more info about what you're doing.

>
>James, did you solve your problem?
>
>
>Thanks in advance,
>
>
>Andrea
>
>
>
>
>[This message was sent through the lwip discussion list.]
>

-- 
James Roth
Shugyo Design Technologies
http://www.shugyodesign.com/



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