|
From: | Darius Babrauskas |
Subject: | Re: [lwip-users] Delayed ACKs |
Date: | Thu, 28 Jan 2016 15:58:37 +0200 |
Hi,
>>When I add delay of 1ms and more
between sending 1272 from PC application the problem disappears.
Maybe, your system “send” driver not testing
“data sending” state. So, new data “overrun” old data.
From: Kaufman, Michael
Sent: Thursday, January 28, 2016 12:30 PM
To: address@hidden
Subject: [lwip-users] Delayed ACKs I am testing lwIP 1.4.1 on Freescale Kinetis K60 tower under
CMX OS. The test sends data in quants of 1272 bytes from the target
(lwIP) to PC host over TCP. Almost immediately a lot of duplicated ACKs and TCP
retransmissions pop out and the speed drops drastically. The same test over UDP works fine, also there is no problem
with TCP in other direction (lwIP sends data to PC). I tried to open debug
output for TCP and saw a bunch of “tcp_fasttmr: delayed ACK”
messages. When I add delay of 1ms and more between sending 1272 from PC
application the problem disappears. I started with
default lwIP TCP settings and then tried to increase TCP window and segment
size, but it doesn’t seem to help. The capture file
attached was with the following configuration: #define
TCP_QUEUE_OOSEQ
1 #define
TCP_MSS
(1500 - 40) #define
TCP_WND
(20*TCP_MSS) In the attached
capture file 10.65.13.12 is a PC host and 192.168.103.48 is a target running
lwIP. I have not much
experience with TCP, so if someone can point me to right direction I will
apreciate it. --
Michael
Kaufman
_______________________________________________ lwip-users mailing list address@hidden https://lists.nongnu.org/mailman/listinfo/lwip-users |
[Prev in Thread] | Current Thread | [Next in Thread] |