perfEvents.h

/*
 * Copyright 2017 Andrei Pangin
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef _PERFEVENTS_H
#define _PERFEVENTS_H

#ifdef __linux__

#include "arch.h"
#include "engine.h"
#include <signal.h>

class PerfEvent;
class PerfEventType;
class StackContext;

class PerfEvents : public Engine {
private:
  static volatile bool _enabled;
  static int _max_events;
  static PerfEvent *_events;
  static PerfEventType *_event_type;
  static long _interval;
  static Ring _ring;
  static CStack _cstack;
  static bool _use_mmap_page;

  // cppcheck-suppress unusedPrivateFunction
  static u64 readCounter(siginfo_t *siginfo, void *ucontext);
  // cppcheck-suppress unusedPrivateFunction
  static void signalHandler(int signo, siginfo_t *siginfo, void *ucontext);

public:
  Error check(Arguments &args);
  Error start(Arguments &args);
  void stop();

  virtual int registerThread(int tid);
  virtual void unregisterThread(int tid);
  long interval() const { return _interval; }

  const char *name() { return "PerfEvents"; }

  static int walkKernel(int tid, const void **callchain, int max_depth,
                        StackContext *java_ctx);

  static void resetBuffer(int tid);

  static const char *getEventName(int event_id);

  inline void enableEvents(bool enabled) { _enabled = enabled; }
};

#else

#include "engine.h"

class StackContext;

class PerfEvents : public Engine {
public:
  Error check(Arguments &args) {
    return Error("PerfEvents are unsupported on this platform");
  }

  Error start(Arguments &args) {
    return Error("PerfEvents are unsupported on this platform");
  }

  static int walkKernel(int tid, const void **callchain, int max_depth,
                        StackContext *java_ctx) {
    return 0;
  }

  inline void enableEvents(bool enabled) {}

  static void resetBuffer(int tid) {}

  static const char *getEventName(int event_id) { return NULL; }

  virtual int registerThread(int tid) { return -1; }
  virtual void unregisterThread(int tid) {}

  long interval() const { return -1; }
};

#endif // __linux__

#endif // _PERFEVENTS_H