Hi all. Sorry in advance for the rash of emails today but the topics
seem to be varying and hopefully folks will read only the ones they
think they could help with.
QUESTIONS:
1) What causes a 'collision' on a network interface?
2) How can I eliminate them? (Including hardware changes if required.)
In looking at this MythTV problem it looks like it's possibly the
networking/NFS side of the equation and not the PVR software side. I'm
running a test using my local drive right now to see if that's true.
In looking at the networking side i see a problem with collisions:
dragonfly ~ # ifconfig
eth0 Link encap:Ethernet HWaddr 00:40:CA:74:21:E9
inet addr:192.168.1.55 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4014229 errors:0 dropped:0 overruns:0 frame:0
TX packets:4014933 errors:0 dropped:0 overruns:0 carrier:0
collisions:1808957 txqueuelen:1000
RX bytes:17072649 (16.2 Mb) TX bytes:3375271889 (3218.9 Mb)
Interrupt:20 Base address:0x9000
myth14 ~ # ifconfig
eth0 Link encap:Ethernet HWaddr 00:11:D8:F4:CD:1D
inet addr:192.168.1.14 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1732167 errors:0 dropped:0 overruns:0 frame:0
TX packets:1592861 errors:0 dropped:0 overruns:0 carrier:0
collisions:289582 txqueuelen:1000
RX bytes:1645387797 (1569.1 Mb) TX bytes:1558513991 (1486.3 Mb)
Interrupt:18 Base address:0xec00
Myth14 is the NFS server. Dragonfly is the NFS client that mounts the
drive. I do not see any collisions on other machines on my network.
Ethernet hardware is built-in to both machines:
dragonfly ~ # lspci | grep Ethernet
0000:01:03.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL-8139/8139C/8139C+ (rev 10)
dragonfly ~ #
myth14 ~ # lspci | grep Ethernet
0000:02:08.0 Ethernet controller: 3Com Corporation 3Com 3C920B-EMB-WNM
Integrated Fast Ethernet Controller (rev 40)
myth14 ~ #
The two machines are connected through a small LinkSys switch. model EZXS55W:
http://www.linksys.com/servlet/Satellite?childpagename=US%2FLayout&packedargs=c%3DL_Product_C2%26cid%3D1115416836711&pagename=Linksys%2FCommon%2FVisitorWrapper
The URL probably won't survive the email.
If I run hdparm -tT on the NFS drive it is using DMA but it's slow, as
it's always been:
myth14 ~ # hdparm -tT /dev/hdc
/dev/hdc:
Timing cached reads: 1544 MB in 2.00 seconds = 771.73 MB/sec
Timing buffered disk reads: 46 MB in 3.11 seconds = 14.77 MB/sec
myth14 ~ #
I'm going to investigate a new kernel on the NFS server side, althoguh
I'm loth to do this since it means messing with LIRC, fglrx and lots
of other touchy stuff. However, if there is a simple way to configure
things so that collisions disappear or go down significantly that
would be great.
Again, thanks in advance and sorry for the number of emails.
Cheers,
Mark
--
gentoo-user@gentoo.org mailing list
