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  <para>One of the key aims of the operating system is to create and support
  the impression that several activities are executing contemporarily. This is
  true for both uniprocessor as well as multiprocessor systems. In the case of
  multiprocessor systems, the activities are trully happening in parallel. The
  scheduler helps to materialize this impression by planning threads on as
  many processors as possible and, when this strategy reaches its limits, by
  quickly switching among threads executing on a single processor.</para>
 
  <section>
    <title>Contexts</title>
 

  </section>
 
  <section>
    <title>Threads</title>
 
    <para>A thread is the basic executable entity with some code and a stack.
    While the code, implemented by a C language function, can be shared by
    several threads, the stack is always private to each instance of the
    thread. Each thread belongs to exactly one task through which it shares
    address space with its sibling threads. Threads that execute purely in the
    kernel don't have any userspace memory allocated. However, when a thread

Subversion Repositories HelenOS-doc

(root)/design/trunk/src/ch_scheduling.xml/ – Rev 140 → 142

Rev 140		Rev 142
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7	<para>One of the key aims of the operating system is to create and support	7	<para>One of the key aims of the operating system is to create and support
8	the impression that several activities are executing contemporarily. This is	8	the impression that several activities are executing contemporarily. This is
9	true for both uniprocessor as well as multiprocessor systems. In the case of	9	true for both uniprocessor as well as multiprocessor systems. In the case of
10	multiprocessor systems, the activities are trully happening in parallel. The	10	multiprocessor systems, the activities are trully happening in parallel. The
11	scheduler helps to materialize this impression by planning threads on as	11	scheduler helps to materialize this impression by planning threads on as
12	many processors as possible and, where this means reaching its limits, by	12	many processors as possible and, when this strategy reaches its limits, by
13	quickly switching among threads executing on a single processor.</para>	13	quickly switching among threads executing on a single processor.</para>
14		14
15	<section>	15	<section>
16	<title>Contexts</title>	16	<title>Contexts</title>
17		17
Line 106...		Line 106...
106	</section>	106	</section>
107		107
108	<section>	108	<section>
109	<title>Threads</title>	109	<title>Threads</title>
110		110
111	<para>A thread is the basic executable entity with a code and a stack.	111	<para>A thread is the basic executable entity with some code and a stack.
112	While the code, implemented by a C language function, can be shared by	112	While the code, implemented by a C language function, can be shared by
113	several threads, the stack is always private to each instance of the	113	several threads, the stack is always private to each instance of the
114	thread. Each thread belongs to exactly one task through which it shares	114	thread. Each thread belongs to exactly one task through which it shares
115	address space with its sibling threads. Threads that execute purely in the	115	address space with its sibling threads. Threads that execute purely in the
116	kernel don't have any userspace memory allocated. However, when a thread	116	kernel don't have any userspace memory allocated. However, when a thread