/*
On an 8-core machine, this takes the top 3-bits
of random numbers and distributes them to the 8 cores
for sorting. Then, it merge sorts them.
*/
#define NUM 1000000
I64 my_mp_cnt=1<<Bsr(mp_cnt);//Power of 2
I32 *arg1,*arg2;
I32 *b[my_mp_cnt],bn[my_mp_cnt];
I64 mp_not_done_flags;
I64 Compare(I32 *e1,I32 *e2)
{
return *e1-*e2;
}
U0 QSortU32(I32 *base,I64 num)
{//By customizing, we dramatically improve it!
//Cut and paste from QSortI64().
I64 i;
I32 *less,*greater,pivot;
if (num>1) {
do {
less=base;
greater=base+num;
pivot=base[num/2];
while (less<greater) {
if (*less<=pivot)
less++;
else {
greater--;
SwapU32(less,greater);
}
}
i=less-base;
if (i==num) {//All less or equ to pivot
//Point greater to first less
do greater--;
while (--i && *greater==pivot);
if (i) {
less=base+num/2; //Pivot was not moved, point to it
if (less<greater)
SwapU32(less,greater);
num=i;
} else //All equ
break;
} else if (i<num/2) {
QSortU32(base,i);
num-=i;
base=greater;
} else {
QSortU32(greater,num-i);
num=i;
}
} while (num>1);
}
}
U0 MPSort(I64 dummy=0)
{
no_warn dummy;
QSortU32(b[Gs->num],bn[Gs->num]);
LBtr(&mp_not_done_flags,Gs->num);
}
U0 MPRadixSortDemo(I64 dummy=0)
{
no_warn dummy;
I64 i,j,k1,k2;
F64 t0;
arg1=MAlloc(NUM*sizeof(I32));
for (i=0;i<NUM;i++)
arg1[i]=RandI32;
arg2=MAlloc(NUM*sizeof(I32));
"$GREEN$QSort$FG$\n";
t0=tS;
MemCpy(arg2,arg1,sizeof(I32)*NUM);
QSort(arg2,NUM,sizeof(I32),&Compare);
"Time:%9.6f\n",tS-t0;
D(arg2+NUM/4);
"$GREEN$QSortU32$FG$\n";
t0=tS;
MemCpy(arg2,arg1,sizeof(I32)*NUM);
QSortU32(arg2,NUM);
"Time:%9.6f\n",tS-t0;
D(arg2+NUM/4);
for (i=0;i<my_mp_cnt;i++) {
//We must do full size, just in case.
//There will be uneven split between cores
//depending on the distribution of rand numbers.
b[i]=MAlloc(NUM*sizeof(I32));
bn[i]=0;
}
if (my_mp_cnt<2) throw('MultCore');
"$GREEN$MP Radix QSortU32$FG$\n";
t0=tS;
k1=32-Bsr(my_mp_cnt);
k2=my_mp_cnt/2;
for (i=0;i<NUM;i++) {
j=arg1[i]>>k1+k2; //This is a preliminary radix sort.
b[j][bn[j]++]=arg1[i];
}
mp_not_done_flags=1<<my_mp_cnt-1;
for (i=0;i<my_mp_cnt;i++)
Spawn(&MPSort,NULL,NULL,i);
while (mp_not_done_flags)
Yield;
j=0;
for (i=0;i<my_mp_cnt;i++) {
MemCpy(&arg2[j],b[i],bn[i]*sizeof(I32));
j+=bn[i];
}
"Time:%9.6f\n",tS-t0;
D(arg2+NUM/4);
Free(arg1);
Free(arg2);
for (i=0;i<my_mp_cnt;i++)
Free(b[i]);
}
MPRadixSortDemo;
/*$HL,0$ Results on 8 Cores 3.397GHz Core i7:
QSort
Time: 0.759998
QSortU32
Time: 0.093684
MP Radix QSortU32
Time: 0.045450
$HL,1$*/