RX buffer details on a KVM host
How can I get RX buffer details on a redhat KVM host ?
Responses
Red Hat
Guru
7257 points
The question isn't exactly clear, but do you wish to see the size of the physical network interface's receive ring buffer?
That's visible with ethtool -g ethX. You can change from the current setting to the maximum with ethtool -G ethX rx XXXX, a full example is given here and the setting can be made permanent by writing ifup-local.
Most drivers show you the current setting and maximum setting, though be2net shows you the maximum size and current ring buffer usage, the maximum size is not configurable on that driver. No other drivers that I know of expose the current usage, you have to infer whether the current setting is too small by looking for ring buffer drops in ethtool -S ethX
If you wish to see current data in socket buffers, that can be done with netstat -n --inet and viewing the Recv-Q column.
Red Hat
Guru
7257 points
A KVM hypervisor is a RHEL system, there is no difference.
Do you mean in the virtual guest? If the interface type is the emulated Intel e1000, then the instructions are the same for the guest OS. If the emulated interface type is the paravirtualized virtio-net interface, that driver does not expose a configurable ring buffer setting, so there's nothing to change.
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