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| − | atomic operation | + | <p>atomic operation<br /> once it starts, it will finish without being interrupted<br /> in database, this is called transaction processing (concurrency control) |
| − | + | </p><p><br /> | |
| − | + | </p><p>ATM1 ATM2<br />balance=1000 <br />1 read balance 5 read balance<br />2 balance-=100 6 balance-=100<br />3 give cash 7 give cash<br />4 update balance 8 update balance<br /> write to db write to db | |
| − | + | </p><p>1<br />1000<br /> 5<br /> 1000<br />2<br />900 | |
| − | ATM1 | + | </p><p>3<br />get $ |
| − | balance=1000 | + | </p><p>6<br /> 900<br /> <br /> 7<br /> get $<br />4<br />db=900<br /> <br /> 8<br /> 900 |
| − | 1 read balance | + | </p><p>class MyThread extends Thread<br />{<br /> private int[] a;<br /> private int[] b;<br /> private int[] c;<br /> private int first;<br /> private int last;<br /> public MyThread (int[] x, int[] y, int[] z, int f int l)<br /> {<br /> a=x;<br /> b=y;<br /> c=z;<br /> first=f;<br /> last=l;<br /> }<br /> public void run()<br /> {<br /> for (int i=first;i<=last;i++)<br /> {<br /> c[i]=a[i]+b[i];<br /> }<br /> }<br />} |
| − | 2 balance-=100 | + | </p><p>int[] a=new int[100];<br />int[] b=new int[100];<br />int[] c=new int[100];<br />initialize a,b,c<br />MyThread t1=new MyThread(a,b,c,0,24);<br />MyThread t2=new MyThread(a,b,c,25,49);<br />MyThread t3=new MyThread(a,b,c,50,74);<br />MyThread t4=new MyThread(a,b,c,75,99);<br />t1.start();<br />t2.start();<br />t3.start();<br />t4.start();<br />t1.join();<br />t2.join();<br />t3.join();<br />t4.join(); |
| − | 3 give cash | + | </p><p>1. do they share data?<br /> false |
| − | 4 update balance 8 update balance | + | </p><p>SIMD S=Single<br />MIMD M=Multiple<br />SISD I=Instruction<br />MISD D=Data<br /> |
| − | + | </p><p><br /> | |
| − | + | } | |
| − | 1 | + | </p><p>int[] a=new int[100]; int[] b=new int[100]; int[] c=new int[100]; initialize a,b,c MyThread t1=new MyThread(a,b,c,0,24); MyThread t2=new MyThread(a,b,c,25,49); MyThread t3=new MyThread(a,b,c,50,74); MyThread t4=new MyThread(a,b,c,75,99); t1.start(); t2.start(); t3.start(); t4.start(); t1.join(); t2.join(); t3.join(); t4.join(); |
| − | 1000 | + | </p><p>1. do they share data? |
| − | + | </p> | |
| − | + | <pre class="_fck_mw_lspace"> false | |
| − | 2 | + | </pre> |
| − | 900 | + | <p>SIMD S=Single MIMD M=Multiple SISD I=Instruction MISD D=Data |
| − | + | </p> | |
| − | 3 | + | |
| − | get $ | + | |
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| − | 4 | + | |
| − | db=900 | + | |
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| − | class MyThread extends Thread | + | |
| − | { | + | |
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| − | + | ||
| − | + | ||
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| − | } | + | |
| − | + | ||
| − | int[] a=new int[100]; | + | |
| − | int[] b=new int[100]; | + | |
| − | int[] c=new int[100]; | + | |
| − | initialize a,b,c | + | |
| − | MyThread t1=new MyThread(a,b,c,0,24); | + | |
| − | MyThread t2=new MyThread(a,b,c,25,49); | + | |
| − | MyThread t3=new MyThread(a,b,c,50,74); | + | |
| − | MyThread t4=new MyThread(a,b,c,75,99); | + | |
| − | t1.start(); | + | |
| − | t2.start(); | + | |
| − | t3.start(); | + | |
| − | t4.start(); | + | |
| − | t1.join(); | + | |
| − | t2.join(); | + | |
| − | t3.join(); | + | |
| − | t4.join(); | + | |
| − | + | ||
| − | 1. do they share data? | + | |
| − | + | ||
| − | + | ||
| − | SIMD | + | |
| − | MIMD | + | |
| − | SISD | + | |
| − | MISD | + | |
Latest revision as of 15:03, 3 November 2010
atomic operation
once it starts, it will finish without being interrupted
in database, this is called transaction processing (concurrency control)
ATM1 ATM2
balance=1000
1 read balance 5 read balance
2 balance-=100 6 balance-=100
3 give cash 7 give cash
4 update balance 8 update balance
write to db write to db
1
1000
5
1000
2
900
3
get $
6
900
7
get $
4
db=900
8
900
class MyThread extends Thread
{
private int[] a;
private int[] b;
private int[] c;
private int first;
private int last;
public MyThread (int[] x, int[] y, int[] z, int f int l)
{
a=x;
b=y;
c=z;
first=f;
last=l;
}
public void run()
{
for (int i=first;i<=last;i++)
{
c[i]=a[i]+b[i];
}
}
}
int[] a=new int[100];
int[] b=new int[100];
int[] c=new int[100];
initialize a,b,c
MyThread t1=new MyThread(a,b,c,0,24);
MyThread t2=new MyThread(a,b,c,25,49);
MyThread t3=new MyThread(a,b,c,50,74);
MyThread t4=new MyThread(a,b,c,75,99);
t1.start();
t2.start();
t3.start();
t4.start();
t1.join();
t2.join();
t3.join();
t4.join();
1. do they share data?
false
SIMD S=Single
MIMD M=Multiple
SISD I=Instruction
MISD D=Data
}
int[] a=new int[100]; int[] b=new int[100]; int[] c=new int[100]; initialize a,b,c MyThread t1=new MyThread(a,b,c,0,24); MyThread t2=new MyThread(a,b,c,25,49); MyThread t3=new MyThread(a,b,c,50,74); MyThread t4=new MyThread(a,b,c,75,99); t1.start(); t2.start(); t3.start(); t4.start(); t1.join(); t2.join(); t3.join(); t4.join();
1. do they share data?
false
SIMD S=Single MIMD M=Multiple SISD I=Instruction MISD D=Data
