[pypy-svn] r23403 - pypy/dist/pypy/doc/discussion

[auc at codespeak.net]

Author: auc
Date: Thu Feb 16 14:51:06 2006
New Revision: 23403

Added:
   pypy/dist/pypy/doc/discussion/oz-thread-api.txt
Log:
api of oz threads


Added: pypy/dist/pypy/doc/discussion/oz-thread-api.txt
==============================================================================
--- (empty file)
+++ pypy/dist/pypy/doc/discussion/oz-thread-api.txt	Thu Feb 16 14:51:06 2006
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+wSome rough notes about the Oz threading model
+=============================================
+
+(almost verbatim from CTM)
+
+Scheduling
+----------
+
+Fair scheduling through round-robin.
+
+With priority levels : three queues exist, which manage high, medium,
+low priority threads. The time slice ratio for these is
+100:10:1. Threads inherit the priority of their parent.
+
+Mozart uses an external timer approach to implement thread preemption.
+
+Thread ops
+----------
+
+All these ops are defined in a Thread namespace/module.
+
+this()               -> current thread's name (*not* another thread's name)
+state(t)             -> return state of t in {runnable, blocked, terminated}
+suspend(t)            : suspend t
+resume(t)             : resume execution of t
+preempt(t)            : preempt t
+terminate(t)          : terminate t immediately
+injectException(t, e) : raise exception e in t
+setPriority(t, p)     : set t's priority to p
+
+Interestingly, coroutines can be build upon this thread
+API. Coroutines have two ops : spawn and resume.
+
+spawn(p)             -> creates a coroutine with procedure p, returns pid
+resume(c)             : transfers control from current coroutine to c
+
+The implementation of these ops in terms of the threads API is as
+follows :
+
+def spawn(p):
+    in_thread:
+        pid = Thread.this()
+        Thread.suspend(pid)
+        p()
+
+def resume(cid):
+    Thread.resume cid
+    Thread.suspend(Thread.this())
+