55 строки
1.6 KiB
Java
55 строки
1.6 KiB
Java
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import shmem.*;
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public class Ring_oshmem
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{
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public static void main(String[] args) throws ShMemException
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{
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ShMem.startPEs(0);
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int nproc = ShMem.getNumPEs();
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int proc = ShMem.getMyPE();
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Addr rbuf = new Addr(4); // One integer value.
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rbuf.putInt(-1);
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int message = 10;
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// Calculate the PE number of the next process in the ring. Use the
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// modulus operator so that the last process "wraps around" to PE 0.
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int next = (proc + 1) % nproc;
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if(proc == 0)
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{
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System.out.println("Process 0 puts message "+ message +" to "+
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next +" ("+ nproc +" processes in ring)");
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rbuf.putInt(message, next);
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}
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// Pass the message around the ring. The exit mechanism works as
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// follows: the message (a positive integer) is passed around the
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// ring. Each time it passes PE 0, it is decremented. When each
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// processes receives a message containing a 0 value, it passes the
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// message on to the next process and then quits. By passing the 0
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// message first, every process gets the 0 message and can quit
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// normally.
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while(message > 0)
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{
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rbuf.waitUntilInt(ShMem.CMP_EQ, message);
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if(proc == 0)
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{
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message--;
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System.out.println("Process 0 decremented value: "+ message);
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}
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rbuf.putInt(message, next);
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if(proc != 0)
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message--;
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}
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// All done
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rbuf.free();
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System.out.println("Process "+ proc +" exiting");
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}
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}
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