Re: [lwip-users] How to optimize raw UDP performance

[Max Bobrov]

Bill: Thank you! disable CHECKSUM_CHECK_UDP and CHECKSUM_GEN_UDP gave
a considerable increase in performance. Xilinx gui interface for lwip
could use some significant improvement to make this and many other
features more accessible.

Chris: I've increased some of these values (listed below) but haven't
seen much improvement from that. Do these look ok or have you had
better success with others?

#define MEM_ALIGNMENT 8
#define MEM_SIZE 262144
#define MEMP_NUM_PBUF 32
#define MEMP_NUM_UDP_PCB 8
#define MEMP_NUM_TCP_PCB 32
#define MEMP_NUM_TCP_PCB_LISTEN 8
#define MEMP_NUM_TCP_SEG 256
#define LWIP_USE_HEAP_FROM_INTERRUPT 1

#define MEMP_NUM_SYS_TIMEOUT 8
#define PBUF_POOL_SIZE 256
#define PBUF_POOL_BUFSIZE 2048
#define PBUF_LINK_HLEN 16


On Wed, Sep 23, 2009 at 11:06 PM, Chris Strahm <address@hidden> wrote:
> Actually someone else reported to me that turning the checksum off in lwIP
> actually made it slower.  I have not checked the reason for this, but that
> was someone else's experience.  There is a big difference in whether you use
> 8/16/32 bit memcpy type routines.  Also if you can write it in asm.  Since
> yours is FPGA, little different.  Also same kind of thing for checksum.  Asm
> will be faster.  Sometimes the difference in how a particular variable or
> address pointer is generated by C can result in very big difference in code.
> You have to look at everything when it comes to high performance.
>
> Also what is the size of your PBUFs and your blocks in your DMA or MAC ISR.
> I assume for a 1G Enet system you probably want the maximum, about 1536
> each.
>
> Chris.
>
>
>
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