jdk8-mips64-public/hotspot: comparison src/share/vm/utilities/yieldingWorkgroup.hpp

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+/*
+* Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*
+*/
+#ifndef SHARE_VM_UTILITIES_YIELDINGWORKGROUP_HPP
+#define SHARE_VM_UTILITIES_YIELDINGWORKGROUP_HPP
+#include "utilities/macros.hpp"
+#include "utilities/workgroup.hpp"
+// Forward declarations
+class YieldingFlexibleWorkGang;
+// Status of tasks
+enum Status {
+INACTIVE,
+ACTIVE,
+YIELDING,
+YIELDED,
+ABORTING,
+ABORTED,
+COMPLETING,
+COMPLETED
+};
+// Class YieldingFlexibleGangWorker:
+//   Several instances of this class run in parallel as workers for a gang.
+class YieldingFlexibleGangWorker: public GangWorker {
+public:
+// Ctor
+YieldingFlexibleGangWorker(AbstractWorkGang* gang, int id) :
+GangWorker(gang, id) { }
+public:
+YieldingFlexibleWorkGang* yf_gang() const
+{ return (YieldingFlexibleWorkGang*)gang(); }
+protected: // Override from parent class
+virtual void loop();
+};
+class FlexibleGangTask: public AbstractGangTask {
+int _actual_size;                      // size of gang obtained
+protected:
+int _requested_size;                   // size of gang requested
+public:
+FlexibleGangTask(const char* name): AbstractGangTask(name),
+_requested_size(0) {}
+// The abstract work method.
+// The argument tells you which member of the gang you are.
+virtual void work(uint worker_id) = 0;
+int requested_size() const { return _requested_size; }
+int actual_size()    const { return _actual_size; }
+void set_requested_size(int sz) { _requested_size = sz; }
+void set_actual_size(int sz)    { _actual_size    = sz; }
+};
+// An abstract task to be worked on by a flexible work gang,
+// and where the workers will periodically yield, usually
+// in response to some condition that is signalled by means
+// that are specific to the task at hand.
+// You subclass this to supply your own work() method.
+// A second feature of this kind of work gang is that
+// it allows for the signalling of certain exceptional
+// conditions that may be encountered during the performance
+// of the task and that may require the task at hand to be
+// `aborted' forthwith. Finally, these gangs are `flexible'
+// in that they can operate at partial capacity with some
+// gang workers waiting on the bench; in other words, the
+// size of the active worker pool can flex (up to an apriori
+// maximum) in response to task requests at certain points.
+// The last part (the flexible part) has not yet been fully
+// fleshed out and is a work in progress.
+class YieldingFlexibleGangTask: public FlexibleGangTask {
+Status _status;
+YieldingFlexibleWorkGang* _gang;
+protected:
+// Constructor and desctructor: only construct subclasses.
+YieldingFlexibleGangTask(const char* name): FlexibleGangTask(name),
+_status(INACTIVE),
+_gang(NULL) { }
+~YieldingFlexibleGangTask() { }
+friend class YieldingFlexibleWorkGang;
+friend class YieldingFlexibleGangWorker;
+NOT_PRODUCT(virtual bool is_YieldingFlexibleGang_task() const {
+return true;
+})
+void set_status(Status s) {
+_status = s;
+}
+YieldingFlexibleWorkGang* gang() {
+return _gang;
+}
+void set_gang(YieldingFlexibleWorkGang* gang) {
+assert(_gang == NULL || gang == NULL, "Clobber without intermediate reset?");
+_gang = gang;
+}
+public:
+// The abstract work method.
+// The argument tells you which member of the gang you are.
+virtual void work(uint worker_id) = 0;
+// Subclasses should call the parent's yield() method
+// after having done any work specific to the subclass.
+virtual void yield();
+// An abstract method supplied by
+// a concrete sub-class which is used by the coordinator
+// to do any "central yielding" work.
+virtual void coordinator_yield() = 0;
+// Subclasses should call the parent's abort() method
+// after having done any work specific to the sunbclass.
+virtual void abort();
+Status status()  const { return _status; }
+bool yielding()  const { return _status == YIELDING; }
+bool yielded()   const { return _status == YIELDED; }
+bool completed() const { return _status == COMPLETED; }
+bool aborted()   const { return _status == ABORTED; }
+bool active()    const { return _status == ACTIVE; }
+};
+// Class YieldingWorkGang: A subclass of WorkGang.
+// In particular, a YieldingWorkGang is made up of
+// YieldingGangWorkers, and provides infrastructure
+// supporting yielding to the "GangOverseer",
+// being the thread that orchestrates the WorkGang via run_task().
+class YieldingFlexibleWorkGang: public FlexibleWorkGang {
+// Here's the public interface to this class.
+public:
+// Constructor and destructor.
+YieldingFlexibleWorkGang(const char* name, uint workers,
+bool are_GC_task_threads);
+YieldingFlexibleGangTask* yielding_task() const {
+assert(task() == NULL || task()->is_YieldingFlexibleGang_task(),
+"Incorrect cast");
+return (YieldingFlexibleGangTask*)task();
+}
+// Allocate a worker and return a pointer to it.
+GangWorker* allocate_worker(uint which);
+// Run a task; returns when the task is done, or the workers yield,
+// or the task is aborted, or the work gang is terminated via stop().
+// A task that has been yielded can be continued via this same interface
+// by using the same task repeatedly as the argument to the call.
+// It is expected that the YieldingFlexibleGangTask carries the appropriate
+// continuation information used by workers to continue the task
+// from its last yield point. Thus, a completed task will return
+// immediately with no actual work having been done by the workers.
+void run_task(AbstractGangTask* task) {
+guarantee(false, "Use start_task instead");
+}
+void start_task(YieldingFlexibleGangTask* new_task);
+void continue_task(YieldingFlexibleGangTask* gang_task);
+// Abort a currently running task, if any; returns when all the workers
+// have stopped working on the current task and have returned to their
+// waiting stations.
+void abort_task();
+// Yield: workers wait at their current working stations
+// until signalled to proceed by the overseer.
+void yield();
+// Abort: workers are expected to return to their waiting
+// stations, whence they are ready for the next task dispatched
+// by the overseer.
+void abort();
+private:
+uint _yielded_workers;
+void wait_for_gang();
+public:
+// Accessors for fields
+uint yielded_workers() const {
+return _yielded_workers;
+}
+private:
+friend class YieldingFlexibleGangWorker;
+void reset(); // NYI
+};
+#endif // SHARE_VM_UTILITIES_YIELDINGWORKGROUP_HPP

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comparison: src/share/vm/utilities/yieldingWorkgroup.hpp

src/share/vm/utilities/yieldingWorkgroup.hpp