In order to fix this problem, I added the following onto the end of the
/etc/sysctl.conf file. I don't know if all of them are necessary, but it takes
a long time to test one by one, waiting for a lost packet and looking through
tcpdumps. Without the tcp_frto change, it was down to a 26 second pause, and
now it just waits for about 40 retransmit requests (still odd), then sends the
lost packet immediately.
net.ipv4.tcp_rmem= 131072 524280 3145728
net.ipv4.tcp_wmem= 131072 1440000 3145728
net.ipv4.tcp_mem= 3145728 3145728 8388608
net.core.wmem_max=3145728
net.core.rmem_max=3145728
net.core.rmem_default=196608
net.core.wmem_default=196608
net.core.optmem_max = 1800000
net.ipv4.tcp_retrans_collapse = 0
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_frto = 0
net.ipv4.tcp_congestion_control = cubic
JK
--- In "naturalwatt" <> wrote:
>
>
>
> --- In "ocean_research_jk" <jonathan.klay@> wrote:
> >
> > I've been struggling all week with this issue. I have a few instruments
> > connected on serial ports. I collect the incoming data and pump it out on a
> > tcp port. When there is a packet lost. I see something like this (although
> > it varies)-
> > packet1
> > ack for 2
> > packet2
> > ack for 3
> > packet4
> > ack for 3 (DUP)
> > (slight pause)
> > packet5 (full size)
> > ack for 3 (DUP)
> > packet6 (full size)
> > ack for 3 (DUP)
> >
> > (pause for 3 to 10 minutes)
> >
> > packet3
> >
> > This long long delay really bogs down the system. I've tried changing some
> > tcp setting like window_scaling, sack, etc. The only improvement was to up
> > the buffer memory, which keeps the connection from getting dropped in some
> > instances, depending on how many segments get lost. Any idea how to get a
> > quicker retransmit?
> >
>
>
> There were some posts on here, some I think from Technologic staff, about
> network problems on the TS7500/7550 series. It is do with the built in NIC,
> apparently, it keeps deconfiguring itself. The Technologic guy said that
> they had been working with the chip vendor and tried lots of documented and
> undocumented internal settings to no avail.
>
> So please feel free to address Technologic directly to ask if they are making
> progress on this problem.
>
> Martin
>
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|