我有一个java程序有13个线程,但其中只有一个是在99%的CPU使用率,并已运行约24小时。其他的CPU使用率为0.0%,并显示从0:00.0
到0:12.82
之间的任一位置的TIME+
,另一个则为3:51.48
。该程序旨在成为一个单线程程序,所以我想知道为什么其他线程在那里?为什么单线程java程序有这么多的线程?
他们在做什么,为什么他们显示如此小的CPU使用率和TIME +?
更新:我有一个旧的Java程序我写的(第一个程序 - 不要审判我!),它是单线程的,并显示了相同类型的线程使用的...
import java.io.*;
class xdriver {
static int N = 100;
static double pi = 3.141592653589793;
static double one = 1.0;
static double two = 2.0;
public static void main(String[] args) {
//System.out.println("Program has started successfully\n");
if(args.length == 1) {
// assume that args[0] is an integer
N = Integer.parseInt(args[0]);
}
// maybe we can get user input later on this ...
int nr = N;
int nt = N;
int np = 2*N;
double dr = 1.0/(double)(nr-1);
double dt = pi/(double)(nt-1);
double dp = (two*pi)/(double)(np-1);
System.out.format("nn --> %d\n", nr*nt*np);
if(nr*nt*np < 0) {
System.out.format("ERROR: nr*nt*np = %d(long) which is %d(int)\n", (long)((long)nr*(long)nt*(long)np), nr*nt*np);
System.exit(1);
}
// inserted to artificially blow up RAM
double[][] dels = new double [nr*nt*np][3];
double[] rs = new double[nr];
double[] ts = new double[nt];
double[] ps = new double[np];
for(int ir = 0; ir < nr; ir++) {
rs[ir] = dr*(double)(ir);
}
for(int it = 0; it < nt; it++) {
ts[it] = dt*(double)(it);
}
for(int ip = 0; ip < np; ip++) {
ps[ip] = dp*(double)(ip);
}
double C = (4.0/3.0)*pi;
C = one/C;
double fint = 0.0;
int ii = 0;
for(int ir = 0; ir < nr; ir++) {
double r = rs[ir];
double r2dr = r*r*dr;
for(int it = 0; it < nt; it++) {
double t = ts[it];
double sint = Math.sin(t);
for(int ip = 0; ip < np; ip++) {
fint += C*r2dr*sint*dt*dp;
dels[ii][0] = dr;
dels[ii][1] = dt;
dels[ii][2] = dp;
}
}
}
System.out.format("N ........ %d\n", N);
System.out.format("fint ..... %15.10f\n", fint);
System.out.format("err ...... %15.10f\n", Math.abs(1.0-fint));
}
}
其中一些可能与垃圾收集有关。它是什么类型的程序?它有GUI吗? –
请发布您的程序! – ganeshvjy
没有GUI - 我指定了'-XX:ParallelGCThreads = 1 -XX:+ UseConcMarkSweepGC',因此它是单线程GC。 – drjrm3