From: Richard Kenner <kenner@gcc.gnu.org>
Date: Fri, 17 May 1996 12:27:31 +0000 (-0400)
Subject: entered into RCS
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b8abf72abbb7370d88a16fb7e2600f386fb41985;p=gcc.git

entered into RCS

From-SVN: r11984
---

diff --git a/gcc/objc/THREADS.MACH b/gcc/objc/THREADS.MACH
new file mode 100644
index 00000000000..55de6637866
--- /dev/null
+++ b/gcc/objc/THREADS.MACH
@@ -0,0 +1,23 @@
+This readme refers to the file thr-mach.c.
+
+Under mach, thread priorities are kinda strange-- any given thread has
+a MAXIMUM priority and a BASE priority.  The BASE priority is the
+current priority of the thread and the MAXIMUM is the maximum possible
+priority the thread can assume.  The developer can lower, but never
+raise the maximum priority.
+
+The gcc concept of thread priorities is that they run at one of three
+levels;  interactive, background, and low.
+
+Under mach, this is translated to:
+
+interactive -- set priority to maximum
+background  -- set priority to 2/3 of maximum
+low         -- set priority to 1/3 of maximum
+
+This means that it is possible for a thread with the priority of
+interactive to actually run at a lower priority than another thread
+with a background, or even low, priority if the developer has modified
+the maximum priority.
+
+