[lwip-users] MEM_SIZE seems to small for TCP_MSS, PBUF_POOL_BUFSIZE

[Sebastian Gniazdowski]

Hello,

I'm using STMicroelectronics's CubeMX which generates RTOS+LwIP code. I have following in opt.h:

#define MEM_SIZE                      2000
#define TCP_MSS                       536
#define TCP_SND_BUF              (2 * TCP_MSS)
#define TCP_SND_QUEUELEN  9
#define PBUF_POOL_SIZE        16
#define PBUF_POOL_BUFSIZE TCP_MSS+40+0+14+4-1 // tailored this formula, 593 and then align

It looks like:

a) 16 * 593 = 9488 is way bigger than 2000

b) 2 * TCP_MSS * 9 = 9648 is also bigger than 2000

I'm concerned especially about pbuf pool. It looks like a plainly preallocated thing, pool size times pool element size, thats all – 9.2 kB of memory to be used. Send buffer and queue looks similar. Am I right and MEM_SIZE should be bigger?

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Best regards,

Sebastian Gniazdowski