On Tue, Sep 21, 2010 at 10:03:10PM +0200, Sander Eikelenboom wrote:
> Hi Konrad,
> I indeed have the feeling the memleak's aren't huge, and adding the diverse
> kernel hacking debug options, ended op doing more wrong than right.
> I have turned off the options i added, re-instated the "swiotlb=force" in the
> domU config to see if it goes from a working to a freezing config, but i have
> the feeling it will not make a difference.
> Then i have 4 differences left:
> - Other dom0 kernel since the tests resulting in continous freezes of my
> - Other domU kernel since the tests resulting in continous freezes of my
> - Other workload (server is running more VM's)
> - Other physical hardware
> - server is AMD phenom X6, current config Intel quad core
> - Both have there iommu disabled
> - Both are 64 capable cpu's with 64 xen, dom0 and domU
> - But most notably perhaps, the intel has only 2GB RAM, the server 8GB
> Could the available physical RAM be an issue here ?
> I limit the ram for dom0 with dom0_mem=
OK, but that would not limit the memory of where the guest get their memory. I
you might need this in conjunction with maxmem, say: maxmem=4GB
This way your 8GB machine has 4GB of memory available for both dom0 and the
> After this test succeeds on the intel machine, i will retry the samen
> xen,dom0 kernel and domU kernel on the AMD config.
> Is there anything i can especially log/configure/debug to get more detail to
> see if the 8GB could be the problem ?
I think we have concluded that the device in question (3.0 PCIe USB host
controller) can do
64-bit DMA. In which case the SWIOTLB is only used as an address translation
(pfn -> mfn, and vice-versa). If it was 32-bit it would also be utilized for
the DMA buffers - there are sometimes cases were the driver does not sync after
(perfect examples are the existing radeon/nouveau drivers) ending up with
device. But those show up early in development, and this is the new USB
can do 64-bit instead of the dreaded 32-bit limit that all other USB
controllers are stuck
The memory difference might be a red-herring. It could be the workload - more
and a latency issue (say we are waiting for an IRQ and it comes just a bit too
I think the idea of narrowing down on the AMD machine the amount of memory
What is the exact model of your USB capture device and the USB PCI device?
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