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[lwip-users] Re: Desired - reference netconn_write() to external memory
From: |
Alan Lamphier |
Subject: |
[lwip-users] Re: Desired - reference netconn_write() to external memory |
Date: |
Wed, 11 Oct 2006 12:22:28 +0000 (UTC) |
User-agent: |
Loom/3.14 (http://gmane.org/) |
Çağlar AKYÜZ <address@hidden> writes:
> > What came to mind today was the possibility to call netconn_write() with
> > NO_COPY, referencing an external memory location instead of pointing to an
> > internal buffer.
> >
> What kind of external memory do you mean? SAM7X does not have any
> external memory bus. Are you using a parallel memory from GPIO?
In my current tests, I am retrieving files from external DataFlash. Eventually
I will be retrieving bulk data from external NAND memory.
> Actually I'm unable to get your problem. If you are facing slow transfer
> rate and want to increase it, then try to give some extra information.
> For instance, I couldn't exceed 5 KBytes per second transfer rate with
> TCP on a SAM7X while I can reach 800 KBytes per second with UDP one the
> same machine.
I seem to be in the ~310KBytes per second range with TCP right now, but I need
yet to test with larger file size transfers. My problem is that the limited
processor RAM makes it difficult to optimize lwIP options for large data
transfers, from what I understand. I had been calling netconn_write(), with the
COPY option as the passing data buffer is reloaded with new data from DataFlash
just after the netconn_write() call - so the original data buffer would not be
intact for retransmissions.
My thought was the possibility to call netconn_write() with the NO_COPY option
and instead of passing a pointer to a RAM data buffer, pass a starting DataFlash
address. Retransmissions could be re-read from DataFlash instead of holding
them in RAM.
Alan
- [lwip-users] Desired - reference netconn_write() to external memory, Alan Lamphier, 2006/10/10
- Re: [lwip-users] Desired - reference netconn_write() to external memory, Kieran Mansley, 2006/10/10
- Re: [lwip-users] Desired - reference netconn_write() to external memory, Çağlar AKYÜZ, 2006/10/11
- [lwip-users] Re: Desired - reference netconn_write() to external memory,
Alan Lamphier <=
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Çağlar AKYÜZ, 2006/10/11
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Kieran Mansley, 2006/10/11
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Kieran Mansley, 2006/10/11
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Çağlar AKYÜZ, 2006/10/11
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Tom Hennen, 2006/10/11
- Re: [lwip-users] Re: Desired - reference netconn_write() to external memory, Çağlar AKYÜZ, 2006/10/11
- [lwip-users] Re: Desired - reference netconn_write()to external memory, Alan Lamphier, 2006/10/11