298 // monitor and execution of each worker as it checks for work
299 // is serialized via the same monitor. The "needs_more_workers()"
300 // call is serialized and additionally the calculation for the
301 // "part" (effectively the worker id for executing the task) is
302 // serialized to give each worker a unique "part". Workers that
303 // are not needed for this tasks (i.e., "_active_workers" have
304 // been started before it, continue to wait for work.
305
306 class FlexibleWorkGang: public WorkGang {
307 // The currently active workers in this gang.
308 // This is a number that is dynamically adjusted
309 // and checked in the run_task() method at each invocation.
310 // As described above _active_workers determines the number
311 // of threads started on a task. It must also be used to
312 // determine completion.
313
314 protected:
315 uint _active_workers;
316 public:
317 // Constructor and destructor.
318 // Initialize active_workers to a minimum value. Setting it to
319 // the parameter "workers" will initialize it to a maximum
320 // value which is not desirable.
321 FlexibleWorkGang(const char* name, uint workers,
322 bool are_GC_task_threads,
323 bool are_ConcurrentGC_threads) :
324 WorkGang(name, workers, are_GC_task_threads, are_ConcurrentGC_threads),
325 _active_workers(UseDynamicNumberOfGCThreads ? 1U : ParallelGCThreads) {}
326 // Accessors for fields
327 virtual uint active_workers() const { return _active_workers; }
328 void set_active_workers(uint v) {
329 assert(v <= _total_workers,
330 "Trying to set more workers active than there are");
331 _active_workers = MIN2(v, _total_workers);
332 assert(v != 0, "Trying to set active workers to 0");
333 _active_workers = MAX2(1U, _active_workers);
334 assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
335 "Unless dynamic should use total workers");
336 }
337 virtual void run_task(AbstractGangTask* task);
338 virtual bool needs_more_workers() const {
339 return _started_workers < _active_workers;
340 }
341 };
342
343 // A class that acts as a synchronisation barrier. Workers enter
344 // the barrier and must wait until all other workers have entered
345 // before any of them may leave.
346
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298 // monitor and execution of each worker as it checks for work
299 // is serialized via the same monitor. The "needs_more_workers()"
300 // call is serialized and additionally the calculation for the
301 // "part" (effectively the worker id for executing the task) is
302 // serialized to give each worker a unique "part". Workers that
303 // are not needed for this tasks (i.e., "_active_workers" have
304 // been started before it, continue to wait for work.
305
306 class FlexibleWorkGang: public WorkGang {
307 // The currently active workers in this gang.
308 // This is a number that is dynamically adjusted
309 // and checked in the run_task() method at each invocation.
310 // As described above _active_workers determines the number
311 // of threads started on a task. It must also be used to
312 // determine completion.
313
314 protected:
315 uint _active_workers;
316 public:
317 // Constructor and destructor.
318 FlexibleWorkGang(const char* name, uint workers,
319 bool are_GC_task_threads,
320 bool are_ConcurrentGC_threads) :
321 WorkGang(name, workers, are_GC_task_threads, are_ConcurrentGC_threads),
322 _active_workers(UseDynamicNumberOfGCThreads ? 1U : workers) {}
323
324 // Accessors for fields.
325 virtual uint active_workers() const { return _active_workers; }
326 void set_active_workers(uint v) {
327 assert(v <= _total_workers,
328 "Trying to set more workers active than there are");
329 _active_workers = MIN2(v, _total_workers);
330 assert(v != 0, "Trying to set active workers to 0");
331 _active_workers = MAX2(1U, _active_workers);
332 assert(UseDynamicNumberOfGCThreads || _active_workers == _total_workers,
333 "Unless dynamic should use total workers");
334 }
335 virtual void run_task(AbstractGangTask* task);
336 virtual bool needs_more_workers() const {
337 return _started_workers < _active_workers;
338 }
339 };
340
341 // A class that acts as a synchronisation barrier. Workers enter
342 // the barrier and must wait until all other workers have entered
343 // before any of them may leave.
344
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