/*
 * Copyright 2013 MongoDB, Inc.
 *
 * 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 MONGOC_COUNTERS_PRIVATE_H
#define MONGOC_COUNTERS_PRIVATE_H

#if !defined (MONGOC_I_AM_A_DRIVER) && !defined (MONGOC_COMPILATION)
#error "Only <mongoc.h> can be included directly."
#endif

#include <bson.h>

#ifdef __linux__
# include <sched.h>
# include <sys/sysinfo.h>
#elif defined(__FreeBSD__) || \
      defined(__NetBSD__) || \
      defined(__DragonFly__) || \
      defined(__OpenBSD__)
# include <sys/types.h>
# include <sys/sysctl.h>
# include <sys/param.h>
#endif


BSON_BEGIN_DECLS


void _mongoc_counters_init (void);


static BSON_INLINE unsigned
_mongoc_get_cpu_count (void)
{
#if defined(__linux__)
   return get_nprocs ();
#elif defined(__FreeBSD__) || \
      defined(__NetBSD__) || \
      defined(__DragonFly__) || \
      defined(__OpenBSD__)
   int mib[2];
   int maxproc;
   size_t len;

   mib[0] = CTL_HW;
   mib[1] = HW_NCPU;
   len = sizeof (maxproc);

   if (-1 == sysctl (mib, 2, &maxproc, &len, NULL, 0)) {
      return 1;
   }

   return len;
#elif defined(__APPLE__) || defined(__sun)
   int ncpu;

   ncpu = (int) sysconf (_SC_NPROCESSORS_ONLN);
   return (ncpu > 0) ? ncpu : 1;
#elif defined(_MSC_VER) || defined(_WIN32)
   SYSTEM_INFO si;
   GetSystemInfo (&si);
   return si.dwNumberOfProcessors;
#else
# warning "_mongoc_get_cpu_count() not supported, defaulting to 1."
   return 1;
#endif
}


#define _mongoc_counter_add(v,count) \
   bson_atomic_int64_add(&(v), (count))


#if defined(ENABLE_RDTSCP)
 static BSON_INLINE unsigned
 _mongoc_sched_getcpu (void)
 {
    volatile uint32_t rax, rdx, aux;
    __asm__ volatile ("rdtscp\n" : "=a" (rax), "=d" (rdx), "=c" (aux) : : );
    return aux;
 }
#elif defined(HAVE_SCHED_GETCPU)
# define _mongoc_sched_getcpu sched_getcpu
#else
# define _mongoc_sched_getcpu() (0)
#endif


#ifndef SLOTS_PER_CACHELINE
# define SLOTS_PER_CACHELINE 8
#endif


typedef struct
{
   int64_t slots [SLOTS_PER_CACHELINE];
} mongoc_counter_slots_t;


typedef struct
{
   mongoc_counter_slots_t *cpus;
} mongoc_counter_t;


#define COUNTER(ident, Category, Name, Description) \
   extern mongoc_counter_t __mongoc_counter_##ident;
#include "mongoc-counters.defs"
#undef COUNTER


enum
{
#define COUNTER(ident, Category, Name, Description) \
   COUNTER_##ident,
#include "mongoc-counters.defs"
#undef COUNTER
   LAST_COUNTER
};


#define COUNTER(ident, Category, Name, Description) \
static BSON_INLINE void \
mongoc_counter_##ident##_add (int64_t val) \
{ \
   _mongoc_counter_add(\
      __mongoc_counter_##ident.cpus[_mongoc_sched_getcpu()].slots[ \
         COUNTER_##ident%SLOTS_PER_CACHELINE], val); \
} \
static BSON_INLINE void \
mongoc_counter_##ident##_inc (void) \
{ \
   mongoc_counter_##ident##_add (1); \
} \
static BSON_INLINE void \
mongoc_counter_##ident##_dec (void) \
{ \
   mongoc_counter_##ident##_add (-1); \
} \
static BSON_INLINE void \
mongoc_counter_##ident##_reset (void) \
{ \
   uint32_t i; \
   for (i = 0; i < _mongoc_get_cpu_count(); i++) { \
      __mongoc_counter_##ident.cpus [i].slots [\
         COUNTER_##ident%SLOTS_PER_CACHELINE] = 0; \
   } \
   bson_memory_barrier (); \
}
#include "mongoc-counters.defs"
#undef COUNTER


BSON_END_DECLS


#endif /* MONGOC_COUNTERS_PRIVATE_H */
