The presentation discusses selfish threads, which are threads that do not yield execution to allow other threads to run. A selfish thread will run continuously in a tight loop without pausing. This can prevent other threads from making progress. The example code shows two threads counting in a loop without yielding. As a result, the threads take turns running for long periods, rather than interleaving their execution. Introducing occasional yields allows threads to alternate more fairly.

1. A PRESENTATION ON
SELFISH THREAD
CREATED BY:
ANKITA TRIPATHI

2. SELFISH THREAD
 Theselfish thread isused to describethreads
that do not ever call yield() or sleep() to
allow other threadsto run.
 let each thread sleepsfor ashort amount of
time. This givestheother thread achanceto
run.
 Every thread should occasionally yield
control to other thread, otherwisethethread
isselfish.
 On someplatforms,aselfish thread can
prevent other threadsfrom making progress.

3. EXAMPLE
public classRunner extendsThread {
Runner(int num){
threadNum = num;
tick = 1;}
public void run() {
while(tick < 4000000) {
if((tick % 100000) == 0)
System.out.println("Tick number " + tick + "of
runner " + threadNum);
tick++; } }
int threadNum;
int tick;}

4. Main method
classRace
{
public static void main(String[] args)
{
Thread runner1 = new Runner(1);
Thread runner2 = new Runner(2);
runner1.start();
runner2.start();
}
}

5. WORKING
 Thewhileloop in therun() method isin atight
loop.
 Oncethescheduler choosesathread with this
thread body for execution, thethread never
voluntarily relinquishescontrol of theCPU
 Thethread continuesto run until thewhileloop
terminatesnaturally or until thethread is
preempted by ahigher priority thread.
 Thisthread iscalled Selfish thread.

6. Selfish output
 Ticknumber100000 of runner1 Ticknumber200000 of
runner1
 Ticknumber300000 of runner1 Ticknumber400000 of
runner1
 Ticknumber500000 of runner1 Ticknumber100000 of
runner2
 Ticknumber200000 of runner2 Ticknumber300000 of
runner2
 Ticknumber400000 of runner2 Ticknumber500000 of
runner2
 Ticknumber600000 of runner2 Ticknumber700000 of
runner2
 Ticknumber800000 of runner2 Ticknumber900000 of
runner2
 Ticknumber600000 of runner1 Ticknumber700000 of
runner1
 Ticknumber800000 of runner1 Ticknumber900000 of
runner1