Re: [lwip-devel] How to estimate heap memory usage (TCP case)

[narke]

On 12 March 2012 12:42, narke <address@hidden> wrote:
> Hi,
>
> I got following run time error:
>
>    166945| tcp_write(pcb=10001db4, data=20082c18, len=1256, apiflags=1)
>    166950| mem_malloc: could not allocate 1328 bytes
>    166950| tcp_write : could not allocate memory for pbuf copy size 1256
>
>
> My configuration is NO_SYS=1 mode, and I was sending data via
> tcp_write.  The COPY_ON_WRITE flag was
> enabled by default.  And, I also disabled the nagle algorithm.  Before
> each time of calling tcp_write, I always call
> snd_buf(), and after each time of tcp_write(), I called tcp_output()
> immediately.
>
> My TCP_MSS is 1388 and TCP_SND_BUF is 4 * TCP_MSS.
>
> I'v already allocated 7K bytes for the heap.  (MEM_SIZE), but it seems
> I still run out of memory.
>
> So, my question is, according to my use pattern.  Can I deduce how
> much heap memory I will need?
> In generate, in the case of SND_BUF = 3 * MSS, to prevent tcp_write()
> from returning error, what the
> peak memory consuming of tcp_write() function?
>
>
> Thanks in advance.
>

Does anyone have an idea?  Thank in advance.