gpu/command_buffer/service/gpu_scheduler.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_
   6 #define GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_
   7
   8 #include <queue>
   9
  10 #include "base/atomic_ref_count.h"
  11 #include "base/atomicops.h"
  12 #include "base/callback.h"
  13 #include "base/memory/linked_ptr.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/memory/shared_memory.h"
  17 #include "base/memory/weak_ptr.h"
  18 #include "gpu/command_buffer/service/cmd_buffer_engine.h"
  19 #include "gpu/command_buffer/service/cmd_parser.h"
  20 #include "gpu/command_buffer/service/command_buffer_service.h"
  21 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
  22 #include "gpu/gpu_export.h"
  23
  24 namespace gfx {
  25 class GLFence;
  26 }
  27
  28 namespace gpu {
  29
  30 class PreemptionFlag
  31     : public base::RefCountedThreadSafe<PreemptionFlag> {
  32  public:
  33   PreemptionFlag() : flag_(0) {}
  34
  35   bool IsSet() { return !base::AtomicRefCountIsZero(&flag_); }
  36   void Set() { base::AtomicRefCountInc(&flag_); }
  37   void Reset() { base::subtle::NoBarrier_Store(&flag_, 0); }
  38
  39  private:
  40   base::AtomicRefCount flag_;
  41
  42   ~PreemptionFlag() {}
  43
  44   friend class base::RefCountedThreadSafe<PreemptionFlag>;
  45 };
  46
  47 // This class schedules commands that have been flushed. They are received via
  48 // a command buffer and forwarded to a command parser. TODO(apatrick): This
  49 // class should not know about the decoder. Do not add additional dependencies
  50 // on it.
  51 class GPU_EXPORT GpuScheduler
  52     : NON_EXPORTED_BASE(public CommandBufferEngine),
  53       public base::SupportsWeakPtr<GpuScheduler> {
  54  public:
  55   GpuScheduler(CommandBufferServiceBase* command_buffer,
  56                AsyncAPIInterface* handler,
  57                gles2::GLES2Decoder* decoder);
  58
  59   virtual ~GpuScheduler();
  60
  61   void PutChanged();
  62
  63   void SetPreemptByFlag(scoped_refptr<PreemptionFlag> flag) {
  64     preemption_flag_ = flag;
  65   }
  66
  67   // Sets whether commands should be processed by this scheduler. Setting to
  68   // false unschedules. Setting to true reschedules. Whether or not the
  69   // scheduler is currently scheduled is "reference counted". Every call with
  70   // false must eventually be paired by a call with true.
  71   void SetScheduled(bool is_scheduled);
  72
  73   // Returns whether the scheduler is currently able to process more commands.
  74   bool IsScheduled();
  75
  76   // Returns whether the scheduler needs to be polled again in the future.
  77   bool HasMoreWork();
  78
  79   typedef base::Callback<void(bool /* scheduled */)> SchedulingChangedCallback;
  80
  81   // Sets a callback that is invoked just before scheduler is rescheduled
  82   // or descheduled. Takes ownership of callback object.
  83   void SetSchedulingChangedCallback(const SchedulingChangedCallback& callback);
  84
  85   // Implementation of CommandBufferEngine.
  86   virtual scoped_refptr<Buffer> GetSharedMemoryBuffer(int32 shm_id) OVERRIDE;
  87   virtual void set_token(int32 token) OVERRIDE;
  88   virtual bool SetGetBuffer(int32 transfer_buffer_id) OVERRIDE;
  89   virtual bool SetGetOffset(int32 offset) OVERRIDE;
  90   virtual int32 GetGetOffset() OVERRIDE;
  91
  92   void SetCommandProcessedCallback(const base::Closure& callback);
  93
  94   void DeferToFence(base::Closure task);
  95
  96   // Polls the fences, invoking callbacks that were waiting to be triggered
  97   // by them and returns whether all fences were complete.
  98   bool PollUnscheduleFences();
  99
 100   bool HasMoreIdleWork();
 101   void PerformIdleWork();
 102
 103   CommandParser* parser() const {
 104     return parser_.get();
 105   }
 106
 107   bool IsPreempted();
 108
 109  private:
 110   // Artificially reschedule if the scheduler is still unscheduled after a
 111   // timeout.
 112   void RescheduleTimeOut();
 113
 114   // The GpuScheduler holds a weak reference to the CommandBuffer. The
 115   // CommandBuffer owns the GpuScheduler and holds a strong reference to it
 116   // through the ProcessCommands callback.
 117   CommandBufferServiceBase* command_buffer_;
 118
 119   // The parser uses this to execute commands.
 120   AsyncAPIInterface* handler_;
 121
 122   // Does not own decoder. TODO(apatrick): The GpuScheduler shouldn't need a
 123   // pointer to the decoder, it is only used to initialize the CommandParser,
 124   // which could be an argument to the constructor, and to determine the
 125   // reason for context lost.
 126   gles2::GLES2Decoder* decoder_;
 127
 128   // TODO(apatrick): The GpuScheduler currently creates and owns the parser.
 129   // This should be an argument to the constructor.
 130   scoped_ptr<CommandParser> parser_;
 131
 132   // Greater than zero if this is waiting to be rescheduled before continuing.
 133   int unscheduled_count_;
 134
 135   // The number of times this scheduler has been artificially rescheduled on
 136   // account of a timeout.
 137   int rescheduled_count_;
 138
 139   // The GpuScheduler will unschedule itself in the event that further GL calls
 140   // are issued to it before all these fences have been crossed by the GPU.
 141   struct UnscheduleFence {
 142     UnscheduleFence(gfx::GLFence* fence, base::Closure task);
 143     ~UnscheduleFence();
 144
 145     scoped_ptr<gfx::GLFence> fence;
 146     base::Time issue_time;
 147     base::Closure task;
 148   };
 149   std::queue<linked_ptr<UnscheduleFence> > unschedule_fences_;
 150
 151   SchedulingChangedCallback scheduling_changed_callback_;
 152   base::Closure descheduled_callback_;
 153   base::Closure command_processed_callback_;
 154
 155   // If non-NULL and |preemption_flag_->IsSet()|, exit PutChanged early.
 156   scoped_refptr<PreemptionFlag> preemption_flag_;
 157   bool was_preempted_;
 158
 159   // A factory for outstanding rescheduling tasks that is invalidated whenever
 160   // the scheduler is rescheduled.
 161   base::WeakPtrFactory<GpuScheduler> reschedule_task_factory_;
 162
 163   DISALLOW_COPY_AND_ASSIGN(GpuScheduler);
 164 };
 165
 166 }  // namespace gpu
 167
 168 #endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_