1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/Design_Notes.txt	Wed Aug 01 01:08:02 2012 -0700
     1.3 @@ -0,0 +1,51 @@
     1.4 +
     1.5 +This test app has to exercise all the aspects of the request handling 
     1.6 +and the assigner code.
     1.7 +
     1.8 +The assigner has two different Qs, plus a set of currentTaskSlvs  check for tasks and also check for explicit VPs.
     1.9 +
    1.10 +So, in the app, make tasks, and also explicit VPs..  create such that they
    1.11 +interleave, cause assigner to switch between.
    1.12 +
    1.13 +So, when start, make some tasks, then make some explicit VPs, then some
    1.14 +tasks, back and forth..  second batch of tasks have inter-dependencies, so
    1.15 +some of the VPs should jump into the middle of them..
    1.16 +
    1.17 +Then, make it so that the last two tasks talk to each other, suspending
    1.18 +each other in turn, (which should cause the extra VPs to dissipate) and
    1.19 +after that they create a bunch more tasks.
    1.20 +
    1.21 +Okay..  what needs to be exercised?
    1.22 +-] create new slave when task suspends
    1.23 +-] dissipate extra slave when have a task one, and no free tasks
    1.24 +-] suspend a task -> no tasks in taskQ -> empty task slave in slaveQ -> 
    1.25 +   dissipate that task slave -> explicit slave next in slaveQ, animate that.
    1.26 +  Means: To get an empty task slave in slaveQ -> create a task that will
    1.27 +   suspend, then create a normal task, which will cause an extra task 
    1.28 +   slave to be created
    1.29 +
    1.30 +===================
    1.31 +To have explicit VPs as well tasks.. add a field to semantic data holds type
    1.32 +of VP: whether it's for running tasks, vs an explicit VP.  when an
    1.33 +explicit dissipates, then switch it to a task VP that has no suspended
    1.34 +tasks..
    1.35 +
    1.36 +So, in the semantic data, have:
    1.37 +-> taskVP vs explicitVP
    1.38 +-> has suspended task vs idle
    1.39 +
    1.40 +Then fix the assigner logic:
    1.41 +When task suspends, get next readyVP, 
    1.42 + check if it's an explicit
    1.43 + and if yes, resume it,
    1.44 + if no, then it's a taskVP, so get next task from taskQ and do it.
    1.45 + Check whether taskQ empty
    1.46 + if yes, then in the state: suspended taskVP, have empty taskVP, no tasks
    1.47 +   so, 
    1.48 +
    1.49 +If taskQ empty, and VP Q empty, return NULL, which will trigger the
    1.50 + back-to-back Master backoff.
    1.51 +
    1.52 +If assigner called and no suspended slaves and taskQ empty..  does it have
    1.53 +a "current task slave"?  If not, create one in the semantic Env.
    1.54 +==================================