Re: [lwip-users] LWIP/WIN32 UDP performance (throughtput)

[Simon Goldschmidt]

"Stephane Lesage" <address@hidden> wrote:
> I need 32 bytes alignement on Blackfin for L1 cache
> and even 128 bytes on C674x for L2 cache.
> 
> I just add this in my cc.h:
> 
> // PBUF_POOL needs to be aligned to cache line size
> #ifndef __cplusplus
> extern u8_t memp_memory_PBUF_POOL_base[] __attribute__ ((aligned (32)));
> #endif
> 
> And in my lwipopts.h:
> 
> #define PBUF_POOL_BUFSIZE                             1520
> // + sizeof(pbuf) = 1536 = 48 cache lines

But then struct pbuf is still only 16 bytes long, so payload might start in the 
middle of a 32-byte border, which leads to faults when flushing cache (since 
the struct pbuf members are still used cached) or am I wrong there?

> But I agree it could be easier with something like:
> #define PBUF_ALIGNMENT        32

That's what I imagined (only with another name maybe).

Simon
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