garnet/lib/perfmon/controller.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef GARNET_LIB_PERFMON_CONTROLLER_H_
#define GARNET_LIB_PERFMON_CONTROLLER_H_

#include <cstdint>
#include <memory>
#include <string>

#include <lib/zircon-internal/device/cpu-trace/perf-mon.h>
#include <lib/zx/vmo.h>
#include <src/lib/fxl/macros.h>

#include "garnet/lib/perfmon/config.h"
#include "garnet/lib/perfmon/properties.h"
#include "garnet/lib/perfmon/reader.h"

namespace perfmon {

class Controller {
 public:
  // The protcol specifies buffer sizes in 4K pages.
  static constexpr uint32_t kLog2PageSize = 12;
  static constexpr uint32_t kPageSize = 1 << kLog2PageSize;
  // The protocol restricts buffer sizes to 256MB.
  static constexpr uint32_t kMaxBufferSizeInPages =
      (256 * 1024 * 1024) / kPageSize;

  // Return true if perfmon is supported on this device.
  static bool IsSupported();

  // Fetch the properties of this device.
  static bool GetProperties(Properties* props);

  static bool Create(uint32_t buffer_size_in_pages, const Config config,
                     std::unique_ptr<Controller>* out_controller);

  // Note: Virtual methods are used here to hide the implementation.
  // There is no intent to provide polymorphism here.

  virtual ~Controller() = default;

  virtual bool Start() = 0;

  // It is ok to call this while stopped.
  virtual void Stop() = 0;

  virtual bool started() const = 0;

  virtual uint32_t num_traces() const = 0;

  virtual const Config& config() const = 0;

  virtual bool GetBufferHandle(const std::string& name, uint32_t trace_num,
                               zx::vmo* out_vmo) = 0;

  virtual std::unique_ptr<Reader> GetReader() = 0;

 protected:
  Controller() = default;

 private:
  static bool Alloc(int fd, uint32_t num_traces, uint32_t buffer_size_in_pages);

  FXL_DISALLOW_COPY_AND_ASSIGN(Controller);
};

}  // namespace perfmon

#endif  // GARNET_LIB_PERFMON_CONTROLLER_H_