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Bug #2776

e1000g jumbo frames don't work with 82579LM

Added by Matthew Bowman over 8 years ago. Updated about 7 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Start date:
2012-05-23
Due date:
% Done:

0%

Estimated time:
Difficulty:
Medium
Tags:
needs-triage
Gerrit CR:

Description

It appears the e1000g driver does not work with jumbo frames with the Intel 82579LM chipset.

I discovered this issue today with a SuperMicro X9SCM-F motherboard which has an Intel 82579LM and an Intel 82574L. My /kernel/drv/e1000g.conf has the correct MaxFrameSize=3,3,0... but I was experience odd network connectivity issues with only one of the NICs (e1000g1 in this case). I reverted back to the default MTU in sheer desperation and everything started working.

mgbowman@oi_151a4:~$ dladm show-linkprop -p mtu
LINK         PROPERTY        PERM VALUE          DEFAULT        POSSIBLE
e1000g0      mtu             rw   9000           1500           1500-9216 
e1000g1      mtu             rw   1500           1500           1500-9216 

I tried various MTUs on the e1000g1 interface and nothing but the 1500 works. Intel says both NICs have Jumbo Frame support so this make me suspect it's a driver issue.

#1

Updated by Enrico Papi over 8 years ago

on oi-151a4, after setting MaxFrameSize=0 and rebooting in noticed the system has already set MTU to:

dladm show-linkprop -p mtu
LINK PROPERTY PERM VALUE DEFAULT POSSIBLE
e1000g0 mtu rw 9216 1500 1500-9216
(don't know if this should happen)

my 82579LM NIC looks OK according dladm/ipadm status, but the system does not receive/send packets.
setting back MaxFrameSize=0, and rebooting, fixes the problem,

sorry but i can not test further here in this system, for example unplumbing the NIC, or removing active interfaces/links on it and setting a different MTU manually.....

#2

Updated by Matthew Bowman over 8 years ago

Did you mean after setting MaxFrameSize = 3 and rebooting you noticed the system had already set the MTU? This happened for me as well but I chalked it up to auto negotiated between my JF enabled switch and the NIC.

Just wanted to add that if you have MaxFrameSize=3 and manually set the MTU to 1500 (my current setup), everything works as expected.

#3

Updated by Rich Ercolani over 8 years ago

Apparently the 82579LM NIC has timing issues that various other e1000 drivers have worked around in other ways - search around with 82579LM and packet loss to find more information.

#4

Updated by Matthew Bowman over 8 years ago

That's a bit unnerving :-/ I was going to use this NIC on a dedicated iSCSI SAN but now I'm thinking I shouldn't.

#5

Updated by Rich Ercolani over 8 years ago

With any of the workarounds, it's been perfectly reliable for me on many systems. For whatever that's worth.

#6

Updated by Yuri Pankov about 7 years ago

Jumbo Frames on 82579LM are working in FreeBSD (10.0-BETA), which is a bit strange, given that we use (nearly) the same code.

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