Re: Lost UDP packets
Re: Lost UDP packets
- Subject: Re: Lost UDP packets
- From: Justin Walker <email@hidden>
- Date: Mon, 27 Sep 2004 12:40:30 -0700
On Sep 27, 2004, at 9:01, Justin Walker wrote:
On Sep 27, 2004, at 7:49, Mark Hunt wrote:
Ok,
A few printf's and some netstat evidence reveals:
The lost packets _are_ being dropped "due to full socket buffers" -
the netstat lost packet count exactly matches the missing packets in
my app.
I'll try to look at the code later today, but FYI, UDP datagrams are
not stored in socket buffers. They are sent as-is to IP (which may
fiddle around if they need to be fragmented; otherwise, they go
straight to the device layer for transmission.
I've reacquainted myself with some of the gnarliest code in creation
(outside the VM arena), and it's definitely the case that UDP datagrams
go straight through the system (like grease through a goose :-})
without ever taking a time to be placed "in" a socket buffer. So the
only part the size of the socket buffer plays is determining whether a
specific datagram can be sent.
I have not tracked down the accounting ("dropped due to full socket
buffers") yet, but will try to slash through the underbrush later
today.
Regards,
Justin
--
Justin C. Walker, Curmudgeon-At-Large *
Institute for General Semantics | If you're not confused,
| You're not paying attention
*--------------------------------------*-------------------------------*
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