[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [lwip-users] losing input packets and repeated acks
From: |
Carl D. Blake |
Subject: |
Re: [lwip-users] losing input packets and repeated acks |
Date: |
Mon, 15 Jan 2007 11:18:37 -0700 |
On Mon, 2007-01-15 at 10:48, Jonathan Larmour wrote:
> > I made the changes you suggested and things are a little better. I'm
> > still getting the huge delay periodically, but the multiple acks of the
> > same packet and the same window size are gone. I still get multiple
> > acks of the same packet, but the system seems to be advertising a larger
> > window size for each ack. I seem to be getting some corrupt data, but
> > it's not nearly as bad as it was before.
>
> Missing data is one thing, but corrupt data implies to me that there is
> something more problematic going on at a lower level, possibly hardware,
> more likely your software ethernet device driver.
>
Hmmm. I'll look at this possibility more closely.
> > I enabled LWIP_STATS and printed out the stats before and after the
> > transfer. TCP stats is reporting several checksum errors. PBUF stats
> > is reporting several errors. I enabled debug messages for pbufs and I'm
> > getting the message "pbuf_alloc: Out of pbufs in pool." This happens
> > quite a bit during the transfer of 1 Mbyte. I hadn't expected this to
> > be a problem since my pbuf memory is 45Kbytes and my TCP window is
> > 16Kbytes. Any other suggestions?
>
> Indeed the remote side should not send more data than the receive window,
> although it may use up a few more pbufs with things like acks. I guess you
> could try and find out where the pbufs are going - it's possible your
> driver might be leaking pbufs. When the stack goes back to quiescent, do
> the stats return to the starting state? i.e. record stats, exchange lots of
> data for a bit, stop exchanging data, record stats again.
>
When the stack is quiescent the stats return to the starting state. The
PBUF stats show 90 available and 0 used. I don't think I'm leaking
pbufs.
> Jifl
- [lwip-users] losing input packets and repeated acks, Carl D. Blake, 2007/01/12
- Re: [lwip-users] losing input packets and repeated acks, Jonathan Larmour, 2007/01/12
- Re: [lwip-users] losing input packets and repeated acks, Jonathan Larmour, 2007/01/12
- Re: [lwip-users] losing input packets and repeated acks, Carl D. Blake, 2007/01/15
- Re: [lwip-users] losing input packets and repeated acks, Jonathan Larmour, 2007/01/15
- Re: [lwip-users] losing input packets and repeated acks,
Carl D. Blake <=
- Re: [lwip-users] losing input packets and repeated acks, Carl D. Blake, 2007/01/16
- Re: [lwip-users] losing input packets and repeated acks, Carl D. Blake, 2007/01/16
- Re: [lwip-users] losing input packets and repeated acks, Jonathan Larmour, 2007/01/16
- Re: [lwip-users] losing input packets and repeated acks, Carl D. Blake, 2007/01/16