Passing tokens between threads

Y. Srinivas Ramakrishna y.s.ramakrishna at
Thu May 6 16:38:03 PDT 2010

Ignore this email; i didn't see your later exchanges with David
Holmes before writing this.

-- ramki

On 05/06/10 16:11, Y. Srinivas Ramakrishna wrote:
> Tony -- let us say the set T of all mutator threads is
> partitioned into disjoint clusters {T_k}, i.e. T = U_k {T_k},
> and for each i, j. T_i \intersect T_k = \empty. I am guessing that
> once a thread t_i becomes a member of a cluster T_k, it stays in
> that cluster until it dies, and that as threads are created
> they either become members of existing clusters or start new clusters?
> Is it the case that there is a single "token" per each cluster,
> and each member of the cluster knows the id of any other member to
> which it wants to pass the token?
> Is that a reasonable description of yr "communication architecture"?
> PS: what is the token used for? is it like a capability or a mutual
> exclusion token?
> I am not sure I understand what is meant by "thread triggering 
> relationship"
> or "how to co-relate two threads together"? Are you talking about how
> to take two arbitrary threads and tell them they are part of
> a cluster and given them the address of the token that they will
> share?
> Anyway, a clear statement of what you want to do would
> probably allow you to find the solution to the problem you are
> trying to solve. (i.e. ask the right questions and the answer
> will reveal itself.)
> best wishes!
> -- ramki
> On 05/06/10 11:59, Tony Guan wrote:
>> Hi David,
>> Thanks for the reply.
>> Actually, my aim is to manipulate the mutator threads inside the VM,
>> because my project is to cluster some threads together, to allocate
>> the objects from the same group(not the ThreadGroup) in certain area
>> of the heap.
>> Inside the VM, I don't quite know how to co-relate two thread together
>> based on the thread triggering relationship.  This is what I am trying
>> to figure out.
>> Thanks again!
>> Tony (Xiaohua Guan)
>> On Wed, May 5, 2010 at 8:28 PM, David Holmes <David.Holmes at> 
>> wrote:
>>> Tony,
>>> Tony Guan said the following on 05/05/10 02:03:
>>>> In my current project, I need to be able to pass tokens between
>>>> certain threads inside VM. While it's easy when Thread A is directly
>>>> calling the Thread B's start().
>>>> But usually, the thread B is not directly created and started by
>>>> thread A, for example, thread pooling. In this case, if I need to pass
>>>> a token from thread A to thread B(which is triggered by A), I guess I
>>>> will need to monitor the object that B is waiting on.
>>>> While I am still pondering over this, is there any other advice?
>>> I don't quite understand what you are asking. In shared-memory
>>> multi-threading the primary communication path between threads is
>>> shared-memory. So passing a "token" is a matter of writing some data 
>>> into a
>>> memory location known to both threads. Then it is just a matter of 
>>> how much
>>> encapsulation/abstraction you want to put around that memory location.
>>> David Holmes

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