Re: Dom0 crash with apache bench (ab)

[Ian Campbell <ian.campbell@citrix.com>]

On Tue, 2015-07-28 at 10:50 -0400, Konrad Rzeszutek Wilk wrote:
> On Tue, Jul 28, 2015 at 03:09:31PM +0200, Christoffer Dall wrote:
> > Hi,
> > 
> > I've been doing some performance comparisons lately, and wanted to 
> > compare
> > the performance overhead of using Xen with apache bench, but 
> > unfortunately
> > the Dom0 kernel crashes when hitting it with ab from a remote machine.
> > Most other workloads seem to be stable, however, I do see similar 
> > crashes
> > if hitting Dom0 mysql with a mysql benchmark with a high level of
> > parallelism.
> > 
> > I use a 10G Mellanox MX354A Dual port FDR CX3 adapter for networking on 
> > a
> > Dell PowerEdge R320 system with a Xeon E5-2450 and 16 GB of RAM.
> > 
> > Interestingly, we had a similarly looking issue on arm64 recently, but 
> > that
> > was fixed with an APM-soecific fix to the hypervisor, so I am guessing 
> > this
> > is unrelated, see:
> > http://lists.xenproject.org/archives/html/xen-devel/2015
> > -03/msg02731.html
> > and the fix:
> > http://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=50dcb3de603927db2fd
> > 87ba09e29c817415aaa44
> > 
> > I have tried with several Linux versions, v3.13, v3.18, v4.0-rc4, and 
> > v4.1,
> > same issue.  I have tried with Xen 4.5-0 release, and the Ubuntu 
> > packaged
> > Xen 4.4 release, same issue.
> > 
> > Examples of crash:
> > http://pastebin.ubuntu.com/11953498/
> > http://pastebin.ubuntu.com/11953443/
> 
> 4.0-rc4?
> 
> Have you tried 4.1?

According to the previous paragraph, yes he has.

> 
> > 
> > Running DomU with a bridge and running ab against apache running in a 
> > DomU
> > also causes the system to crash.
> > 
> > Note: The server also has an embedded 1G Broadcom NIC (although not
> > suitable for testing due to it being 1G and on a control network), and
> > using that for the test does not cause a system crash, so this points 
> > to
> > some difficulties with the Mellanox device and Xen.
> > 
> > Any ideas or advice is greatly appreciated, thanks.
> > 
> > -Christoffer
> 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xen.org
> > http://lists.xen.org/xen-devel
> 
> 
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