Let's first understand what is LSO stands for and what is the purpose of using LSO.
As you see above LSO stands for Large Segment Offload.
TCP Offload Engine is an embryonic technology which is designed to offload TCP stack handling from the main system CPU to a processor built into NIC cards, hence the no CPU cycle and kernel time will get consumed.
LSO saves valuable CPU cycles by allowing the network protocol stack to handle large segments instead of the traditional model of MSS (TCP Maximum Segment Size) sized segments. In the traditional network stack, the TCP layer segments the outgoing data into the MSS sized segments and passes them down to the driver. This becomes computationally expensive with 10 GigE networking because of the large number of kernel functional calls required for every MSS segment. With LSO, a large segment is passed by TCP to the driver, and the driver or NIC hardware does the job of TCP segmentation (LSO offload the segmentation job on Layer 4 to the NIC driver). An LSO segment may be as large as 64 KByte. The larger the LSO segment, better the CPU efficiency since the network stack has to work with smaller number of segments for the same throughput.
3.The driver for this network card is capable of handling it.
Ways to disable LSO -
Disable LSO by adding the following line in the /kernel/drv/e1000g.conf file (I’m using the e1000g interface/driver hence the file that I'm using is /kernel/drv/e1000g.conf) :
Also if you don't want to reboot the server after modifying the file /kernel/drv/e1000g.conf you can simply unplumb all of your e1000g interfaces with ifconfig, do "update_drv e1000g" to reload the .conf file, and then replumb and reconfigure the interfaces with ifconfig however still if I'm going to unplumb the network interfaces then eventually I'll be disturbing the services so reboot is the best option.
I had to disable the LSO as our application folks were experiencing slowness in their web application (response time etc.) It looks like LSO cause unstable connections & hence there are few observations like dropped sockets, dropped packets, packet reordering, packet retransmits and ultimately application folks observed slowness in their web application, NFS stuffs etc.