Re: [Qemu-devel] [Bug 1556306] Re: vhost-user: qemu stops processing packets under high load of traffic

[Michael S. Tsirkin]

On Fri, Mar 11, 2016 at 10:51:33PM -0000, Vincent JARDIN wrote:
> for tracking,
>   
> http://git.qemu.org/?p=qemu.git;a=patch;h=5669655aafdb88a8797c74a989dd0c0ebb1349fa
> 
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> https://bugs.launchpad.net/bugs/1556306
> 
> Title:
>    vhost-user: qemu stops processing packets under high load of traffic
> 
> Status in QEMU:
>   New

I presume you'll also close this bu at some point?
It's fixed in upstream QEMU.

> Bug description:
>   Description of problem:
>   - qemu socket becomes full, causing qemu to send incomplete
>   SET_VRING_CALL messages to vhost-user backend (without proper fd set in
>   ancillary data).
>   - after some time, some interrupts are lost, causing the VM to stop
>   transmitting packets.
> 
>   How reproducible:
>   Run a stress tests of a vhost-user interface using an UDP
>   traffic generator. Traffic generator (IXIA) was connected to 2 physical 
> ports that are in turn connected to 2 virtio ports through a linux bridge, VM
>   (running linux) doing routing to forward packets between the 2 virtio ports.
>   When traffic reaches high pps rates of small packets,
> 
>   Actual results:
>   - VM stop transmitting packets
> 
>   Expected results:
>   - VM should never stop transmitting packets
> 
>   Additional info:
>   We do propose a fix at:
>     http://lists.nongnu.org/archive/html/qemu-devel/2015-12/msg00652.html
> 
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