116 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
			
		
		
	
	
			116 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
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<html>
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<head>
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<title>parallelvm</title>
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<link rel="stylesheet" type="text/css" media="all" href="../man.css">
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</head>
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<body bgcolor=#ffffff>
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<h2 align=center>parallelvm</h2>
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<h4 align=center>OS/161 Reference Manual</h4>
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<h3>Name</h3>
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<p>
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parallelvm - concurrent VM system test
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</p>
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<h3>Synopsis</h3>
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<p>
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<tt>/testbin/parallelvm</tt> [<tt>-w</tt>]
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</p>
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<h3>Description</h3>
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<p>
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<tt>parallelvm</tt> runs a fairly large number (24) of fairly small
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processes in parallel to stress your VM system. The processes perform
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aimless matrix operations.
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</p>
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<p>
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Before attempting <tt>parallevm</tt> make sure the <tt>zero</tt> test
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passes; <tt>parallelvm</tt> will fail with wrong answers if its BSS
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doesn't start out zeroed. Also, it may be helpful to get it running
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successfully purely in RAM before cutting back the memory size so it
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swaps.
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</p>
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<p>
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If your VM system's fork is particularly slow, you will probably find
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that the early processes exit before the later ones finish forking.
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This reduces the total memory load and can easily cause
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<tt>parallelvm</tt> to run completely in RAM without needing to swap;
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this in turn makes it a much less effective stress test.
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</p>
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<p>
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For this reason, the <tt>-w</tt> option can be used to make all the
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subprocesses sync up before starting to compute.
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They use user-level semaphores for coordination.
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</p>
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<p>
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If benchmarking, always use <tt>-w</tt>.
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</p>
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<h3>Requirements</h3>
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<p>
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<tt>parallelvm</tt> uses the following system calls:
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<ul>
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<li> <A HREF=../syscall/getpid.html>getpid</A>
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<li> <A HREF=../syscall/fork.html>fork</A>
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<li> <A HREF=../syscall/fork.html>waitpid</A>
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<li> <A HREF=../syscall/write.html>write</A>
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<li> <A HREF=../syscall/_exit.html>_exit</A>
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</ul>
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</p>
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<p>
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Adding the <tt>-w</tt> option also uses:
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<ul>
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<li> <A HREF=../syscall/open.html>open</A>
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<li> <A HREF=../syscall/write.html>read</A>
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<li> <A HREF=../syscall/close.html>close</A>
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<li> <A HREF=../syscall/remove.html>remove</A>
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</ul>
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</p>
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<p>
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<tt>parallelvm</tt> should run properly once your VM system is complete.
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</p>
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<p>
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Until the remove system call has been implemented, which is
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typically not part of the basic system calls assignment,
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<tt>parallelvm -w</tt> will be unable to clean up its semaphores.
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This is merely untidy and not a real problem.
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</p>
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</body>
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</html>
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