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#define THREADED_RTS
#include "Rts.h"
#include "WSDeque.h"
#include <stdio.h>
#define SCRATCH_SIZE (1024*1024)
#define THREADS 3
#define POP 2
WSDeque *q;
StgWord scratch[SCRATCH_SIZE];
StgWord done;
OSThreadId ids[THREADS];
// -----------------------------------------------------------------------------
// version of stealWSDeque() that logs its actions, for debugging
#ifdef DEBUG
#define BUF 128
int bufs[THREADS];
StgWord last_b[THREADS][BUF];
StgWord last_t[THREADS][BUF];
StgWord last_v[THREADS][BUF];
#define CASTOP(addr,old,new) ((old) == cas(((StgPtr)addr),(old),(new)))
void *
myStealWSDeque_ (WSDeque *q, nat n)
{
void * stolen;
StgWord b,t;
// Can't do this on someone else's spark pool:
// ASSERT_WSDEQUE_INVARIANTS(q);
// NB. these loads must be ordered, otherwise there is a race
// between steal and pop.
t = q->top;
load_load_barrier();
b = q->bottom;
// NB. b and t are unsigned; we need a signed value for the test
// below, because it is possible that t > b during a
// concurrent popWSQueue() operation.
if ((long)b - (long)t <= 0 ) {
return NULL; /* already looks empty, abort */
}
/* now access array, see pushBottom() */
stolen = q->elements[t & q->moduloSize];
/* now decide whether we have won */
if ( !(CASTOP(&(q->top),t,t+1)) ) {
/* lost the race, someon else has changed top in the meantime */
return NULL;
} /* else: OK, top has been incremented by the cas call */
// debugBelch("stealWSDeque_: t=%d b=%d\n", t, b);
// Can't do this on someone else's spark pool:
// ASSERT_WSDEQUE_INVARIANTS(q);
bufs[n] ++;
if (bufs[n] == BUF) { bufs[n] = 0; }
last_b[n][bufs[n]] = b;
last_t[n][bufs[n]] = t;
last_v[n][bufs[n]] = (StgWord)stolen;
return stolen;
}
void *
myStealWSDeque (WSDeque *q, nat n)
{
void *stolen;
do {
stolen = myStealWSDeque_(q,n);
} while (stolen == NULL && !looksEmptyWSDeque(q));
return stolen;
}
void dump(void)
{
nat n;
nat i;
for (n = 0; n < THREADS; n++) {
debugBelch("\nthread %d:\n", n);
for (i = bufs[n]; i >= stg_max(bufs[n]-20,0); i--) {
debugBelch("%d: t=%ld b=%ld = %ld\n", i, last_t[n][i], last_b[n][i], last_v[n][i]);
}
}
}
#endif // DEBUG
// -----------------------------------------------------------------------------
void work(void *p, nat n)
{
StgWord val;
// debugBelch("work %ld %d\n", p, n);
val = *(StgWord *)p;
if (val != 0) {
fflush(stdout);
fflush(stderr);
barf("FAIL: %ld %d %d", p, n, val);
}
*(StgWord*)p = n+10;
}
void OSThreadProcAttr thief(void *info)
{
void *p;
StgWord n;
nat count = 0;
n = (StgWord)info;
while (!done) {
#ifdef DEBUG
p = myStealWSDeque(q,n);
#else
p = stealWSDeque(q);
#endif
if (p != NULL) { work(p,n+1); count++; }
}
debugBelch("thread %ld finished, stole %d", n, count);
}
int main(int argc, char*argv[])
{
int n;
nat count = 0;
void *p;
q = newWSDeque(1024);
done = 0;
for (n=0; n < SCRATCH_SIZE; n++) {
scratch[n] = 0;
}
for (n=0; n < THREADS; n++) {
createOSThread(&ids[n], thief, (void*)(StgWord)n);
}
for (n=0; n < SCRATCH_SIZE; n++) {
if (n % POP) {
p = popWSDeque(q);
if (p != NULL) { work(p,0); count++; }
}
pushWSDeque(q,&scratch[n]);
}
#ifdef DEBUG
debugBelch("main thread finished, popped %d", count);
#endif
exit(0);
}
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