I'm afraid the only documentation is the source code itself. Look in
tools/xentrace.c, and xen/common/trace.c. The basic idea is that the
page is a ring buffer with producer and consumer pointers. Xen always
writes a record, then updates the producer; xentrace always reads a
record, then updates the consumer. If incrementing the producer would
clobber a consumer, then Xen just drops the trace record.
On Thu, Aug 6, 2009 at 3:04 PM, Derek
> On Thu, Aug 6, 2009 at 9:01 AM, Derek Riley
> <derek.riley@xxxxxxxxxxxxxxxxxxx> wrote:
>> Thanks for your response. I am working with the Xen Hypervisor, but I am
>> not familiar with xentrace. I found some information about it through
>> google searches, but I was unable to discover how it uses the shared page
>> you mentioned. Do you have any links to point me in the right direction?
>> On Mon, Aug 3, 2009 at 12:17 PM, George Dunlap
>> <George.Dunlap@xxxxxxxxxxxxx> wrote:
>>> I assume you mean "Xen Hypervisor" (as the kernel would be probably
>>> Linux dom0 kernel)?
>>> You might look at the xentrace mechanism for using a shared page to
>>> pass information out of Xen. You could probably adapt the same idea
>>> to pass information into Xen if you needed to.
>>> On Fri, Jul 31, 2009 at 5:39 PM, Derek
>>> Riley<derek.riley@xxxxxxxxxxxxxxxxxxx> wrote:
>>> > Hello-
>>> > I am working on a project to modify Xen to precisely control the
>>> > execution
>>> > times of the individual guest domains, and I need some help. I
>>> > considered
>>> > modifying the XM python program, but it is not precise or fast enough
>>> > for my
>>> > application.
>>> > I want to be able to pass short, simple message quickly between an
>>> > application-level process and the Xen kernel asynchonously. I found an
>>> > IPC
>>> > mechanism designed for the method called netlink
>>> > (http://www.linuxjournal.com/article/7356), but I am not sure how to
>>> > incorporate it into the Xen kernel. When I attempt to recompile the
>>> > kernel
>>> > with netlink, I get errors that seem to stem from type issues I am not
>>> > familiar with.
>>> > 2 questions:
>>> > Is it possible to use a mechanism such as netlink with Xen? If so,
>>> > how?
>>> > Is there other functionality within Xen that could be used with minimal
>>> > modification to do IPC within domain0?
>>> > Any help/advice would be greatly appreciated. Thanks!
>>> > --Derek
>>> > _______________________________________________
>>> > Xen-devel mailing list
>>> > Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> > http://lists.xensource.com/xen-devel
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