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#include <u.h>
#include <libc.h>
#include <thread.h>
typedef struct Ttask Ttask;
typedef struct Taskq Taskq;
typedef struct Tpool Tpool;
struct Ttask
{
void (*fn)(void*);
void *arg;
Ttask *next;
};
struct Taskq
{
Ttask *hd;
Ttask *tl;
};
struct Tpool
{
QLock;
Rendez empty;
ulong nprocs;
Ref nworking;
Taskq subq; /* task submission queue */
Channel *done; /* task completion signal */
};
void
taskqput(Tpool *tp, Ttask *t)
{
qlock(tp);
if(tp->subq.tl == nil){
tp->subq.hd = tp->subq.tl = t;
rwakeup(&tp->empty);
qunlock(tp);
return;
}
tp->subq.tl->next = t;
tp->subq.tl = t;
rwakeup(&tp->empty);
qunlock(tp);
}
Ttask *
taskqget(Tpool *tp)
{
Ttask *t;
qlock(tp);
while(tp->subq.hd == nil)
rsleep(&tp->empty);
t = tp->subq.hd;
tp->subq.hd = t->next;
t->next = nil;
if(tp->subq.hd == nil)
tp->subq.tl = nil;
qunlock(tp);
return t;
}
void
threadloop(void *arg)
{
Tpool *pool;
Ttask *task;
pool = arg;
for(;;){
task = taskqget(pool);
if(task == nil)
continue;
incref(&pool->nworking);
task->fn(task->arg);
decref(&pool->nworking);
nbsend(pool->done, nil);
}
}
Tpool *
mkthreadpool(ulong nprocs)
{
Tpool *tp;
tp = malloc(sizeof *tp);
memset(tp, 0, sizeof *tp);
tp->empty.l = &tp->QLock;
tp->nprocs = nprocs;
tp->done = chancreate(sizeof(void*), 0);
while(nprocs--)
proccreate(threadloop, tp, mainstacksize);
return tp;
}
void
threadpoolexec(Tpool *tp, void (*fn)(void*), void *arg)
{
Ttask *t;
t = malloc(sizeof *t);
memset(t, 0, sizeof *t);
t->fn = fn;
t->arg = arg;
taskqput(tp, t);
}
typedef struct Tsum Tsum;
struct Tsum
{
int a;
int b;
};
void
sum(void *arg)
{
Tsum *sum;
int cnt;
sum = arg;
cnt = 100;
while(cnt--) sum->a = sum->a+sum->b;
}
void
usage(void)
{
fprint(2, "usage: %s [-t] [-n nprocs]\n", argv0);
exits(nil);
}
void
threadmain(int argc, char *argv[])
{
static int W = 1000, H = 1000;
Tpool *pool;
Tsum *t;
int i, j;
int threaded;
int nprocs;
threaded = 0;
nprocs = 8;
ARGBEGIN{
case 't': threaded++; break;
case 'n': nprocs = strtoul(EARGF(usage()), nil, 0); break;
default: usage();
}ARGEND;
if(argc != 0)
usage();
t = malloc(W*H*sizeof(*t));
if(threaded){
pool = mkthreadpool(nprocs);
for(i = 0; i < H; i++)
for(j = 0; j < W; j++){
t[i*W+j] = (Tsum){i, j};
threadpoolexec(pool, sum, &t[i*W+j]);
}
while(pool->nworking.ref > 0)
recvp(pool->done);
threadexitsall(nil);
}
for(i = 0; i < H; i++)
for(j = 0; j < W; j++){
t[i*W+j] = (Tsum){i, j};
sum(&t[i*W+j]);
}
exits(nil);
}
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