Changes between Version 61 and Version 62 of LightweightConcurrency

Timestamp:

05/20/12 15:41:54 (12 months ago)

Author:

kc

Comment:

--

LightweightConcurrency

@@ -19 +19 @@
   * [#Schedulers Schedulers]
   * [#MVars MVars]
- * [#CapabilitiesandTasks Capabilities and Tasks]
+ * [#ParallelismandSystemThreads Parallelism and System Threads]
+  * [#TaskModel Task Model]
   * [#SContAffinity SCont Affinity]
   * [#BoundSCont Bound SCont]
@@ -257 +258 @@
 As an aside, the race condition in [http://www.haskell.org/ghc/docs/6.12.2/html/libraries/base-4.2.0.1/Control-Concurrent-MVar.html#v%3AswapMVar swapMVar] can be eliminated with the help of PTM abstraction. TODO: show example. Thus, PTM abstraction makes it easy to construct correct concurrent data-structures. 
 
-== Capabilities and Tasks ==
+== Parallelism and System Threads ==
 
 Whatever be the concurrency model, we would like to retain the non-programmatic control over parallelism (using +RTS -N). Just like in the current system, this runtime parameter controls the number of capabilities. Cores are system resources and hence, the control over their allocation to different processes should be a property of the context under which the programs are run. For example, in a multi-programmed environment, it might be wiser to run the programs on a fewer cores than available to avoid thrashing. At the very least, this will avoid the cases where a poorly written concurrency library would not bring down the performance of the entire system. 
+
+=== Task Model ===
 
 We retain the task model of the current runtime system. There is a one-to-one mapping between tasks and system threads. Tasks are not exposed to the programmer and is transparently managed by the RTS.
@@ -285 +288 @@
 
 Creating a bound SCont creates a new task, which is the only task capable of running the bound SCont. When switching to a bound SCont, the RTS transparently switches to the corresponding bound task. Similarly, when switching away from a bound SCont, the RTS suspends the current bound task, and switches to another appropriate task. However, an unbounded SCont (created through `newSCont` primitive) might be run on any unbounded task (referred to as worker tasks). New worker tasks might be created by the RTS on demand.
-
-== Scaling on Multicores ==
 
 == Scheduler Interaction with RTS ==