Re: [BUG] VIF rate limiting locks up network in the whole system

[Jacek Konieczny <jajcus@jajcus.net>]

On 05/09/14 11:18, Ian Campbell wrote:
> On Fri, 2014-05-09 at 09:03 +0200, Jacek Konieczny wrote:
>> Hi,
>>
>> [third attempt to send this to the xen-devel list]
>>
>> To prevent a single domU from saturating our bandwidth we use the
>> 'rate=...' options in VIF configuration of our domains xl.cfg files.
>> This used to work without serious issues, but recently, after upgrading
>> to xen 4.4.0 something went wrong.
> 
> Just to be clear, you changed Xen but not the dom0 or domU kernel, is
> that right?

Unfortunately not, I have upgraded all.

> Which version of Xen were you using before?

4.3.1

> Did you also change toolstack (e.g. from xm to xl) over the upgrade?

No, I have been using 'xl' for long time now.

> The main (only, I think) affect of the rate= from the toolstack PoV is
> to write some additional keys to the vif backend directory, you should
> be able to see this in "xenstore-ls -fp" output.

I could have guessed that.

> Do they perhaps differ between the working and non-working case
> (despite the input configuration being the same)?

I will check that. I think this can be safely done even on a production
server, still running the old Xen and kernel.

> Those keys then affect netback's behaviour which is why I am interested
> in whether the kernel version has changed.

The kernel version has changed and I should focus on that instead of the
Xen version change.

I will try other kernels and get more information.

The other thing is I am not 100% sure my earlier setups were not buggy –
it might be I have just never reached the limit for long enough to notice.

Greets,
	Jacek