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VS: [lwip-users] speed and delay question with uc/os-ii
From: |
Jarkko Loima |
Subject: |
VS: [lwip-users] speed and delay question with uc/os-ii |
Date: |
Thu, 26 Aug 2004 19:22:50 +0300 |
Hi!
I noticed that, windows 2k & CAsynckSocket was bottleneck, not lwip. I
still have a little delay and CRC-failures otherwise system works fine.
-Jarkko
>Thanks for quick answer.
>
>I have to send either (4260) Bytes once in 100mS or 73 Bytes in every
2mSec...
>
>Buffering & sending data with TCP is more reliable way but it takes
about 20mSec to send that packet. Reason for problems >is that i'm using
interrupt driven system and sending data through TCP overrides all lower
level interrupts. If i chabge >prioritys of interrupts incoming data is
ok but TCP-start's sending out of order & retransmissions...
>
>So what would you suggest? Do you think that i could send UDP-packet
once in every 2mSec?
>
>Other end is w2k Visual C++, program with casynckSocket...
>
>-JLoima
Quoting "K.J. Mansley" <address@hidden>:
> On Wed, 2004-08-25 at 09:13, address@hidden wrote:
> > Hi!
> >
> > I'm using lwip with uc/os-ii. I'd like to know which is the wastest
> > &
> delayless
> > way to send data (size of data to send is about 4260 Bytes).
> >
> > I'm using TCP with netconn_write() at the moment but have a little
> > problems
> with
> > delay (20 ms) & retransmissions...
> >
> > So, is UPD faster way or should i use tcp_write() or something like
> > that???
> I
> > think that with UDP i could get rid of these retransmissions.
>
> The raw API (e.g. tcp_write() etc) will be faster than using netconn_*
>
> UDP may make a small difference, as it's a simpler protocol, but if
> you're losing data you'll need to do retransmissions whatever
> transport protocol you choose. I would try to work out why data need
> to be retransmitted, and address that. If you are just doing a single
> short transfer over each connection you may find UDP helps by not
> having the "slow start" phase of TCP.
>
> Hope that helps,
>
> Kieran
>
>
>
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