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Re: [rhelv6-list] Kernel errors under kvm guest using e1000

On 04/20/2011 01:36 PM, John Haxby wrote:
So you think the virtual ne2k_pci or rtl8139 limit the bandwidth to the
same as the driver for real hardware? Or, for that matter, that
virtio_net is limiting the speed to 1GB?

You should find that guest to guest communication through virtual
interfaces is limited by the performance of the host and guest to
external machine is limited by the minimum of the raw machine
performance and the physical NIC.   Is this not the case?

Here I get about 80MB/s between guests (admitedly using xen rather than
kvm, but the principle is the same) even though the emulated NIC says
100Mb/s, which is rather less than the 700Mb/s I'm actually getting.
(This is not a particularly quick machine either and in fact I'm limited
by how quckly I'm pulling data off a disk, the maximum attainable speed
without that is much, much greater).

No, I am not saying that virtual ne2k_pci or rtl8193 limit the bandwidth. I have test it.

Using ne2k_pci or rtl8193, bandwidth is 1MB/s-850KB/s, very horrible ... Using e1000 driver bandwidth starts at 87-80MB/s at start and after some some seconds, bandwidth is degraded until is stalled, for example copying a 600MB file using scp ...

But doesn't occurs for example using e1000 driver under vmware (workstation or esxi). Bandwidth is stable.

CL Martinez
carlopmart {at} gmail {d0t} com

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