x15/kern/syscnt.h

/*
 * Copyright (c) 2014-2019 Richard Braun.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * System counters.
 *
 * This module provides 64-bits general-purpose counters that can be
 * accessed and modified atomically from any context.
 */

#ifndef KERN_SYSCNT_H
#define KERN_SYSCNT_H

#include <stdint.h>

#include <kern/atomic.h>
#include <kern/init.h>
#include <kern/macros.h>
#include <kern/spinlock.h>
#include <kern/stream.h>

// Size of the buffer storing a system counter name.
#define SYSCNT_NAME_SIZE   32

#include <kern/syscnt_types.h>

// System counter.
struct syscnt;

/*
 * Initialize and register the given counter.
 *
 * The counter is set to 0.
 */
void syscnt_register (struct syscnt *syscnt, const char *name);

#ifdef ATOMIC_HAVE_64B_OPS

static inline void
syscnt_set (struct syscnt *syscnt, uint64_t value)
{
  atomic_store_rlx (&syscnt->value, value);
}

static inline void
syscnt_add (struct syscnt *syscnt, int64_t delta)
{
  atomic_add_rlx (&syscnt->value, delta);
}

static inline uint64_t
syscnt_read (const struct syscnt *syscnt)
{
  return (atomic_load_rlx ((uint64_t *)&syscnt->value));
}

#else

static inline void
syscnt_set (struct syscnt *syscnt, uint64_t value)
{
  cpu_flags_t flags;
  spinlock_lock_intr_save (&syscnt->lock, &flags);
  syscnt->value = value;
  spinlock_unlock_intr_restore (&syscnt->lock, flags);
}

static inline void
syscnt_add (struct syscnt *syscnt, int64_t delta)
{
  cpu_flags_t flags;
  spinlock_lock_intr_save (&syscnt->lock, &flags);
  syscnt->value += delta;
  spinlock_unlock_intr_restore (&syscnt->lock, flags);
}

static inline uint64_t
syscnt_read (struct syscnt *syscnt)
{
  cpu_flags_t flags;
  spinlock_lock_intr_save (&syscnt->lock, &flags);

  uint64_t value = syscnt->value;
  spinlock_unlock_intr_restore (&syscnt->lock, flags);
  return (value);
}

#endif

static inline void
syscnt_inc (struct syscnt *syscnt)
{
  syscnt_add (syscnt, 1);
}

static inline void
syscnt_dec (struct syscnt *syscnt)
{
  syscnt_add (syscnt, -1);
}

/*
 * Display system counters.
 *
 * A prefix can be used to filter the output, where only counters with the
 * given prefix are displayed. If NULL, all counters are reported.
 */
void syscnt_info (const char *prefix, struct stream *stream);

/*
 * This init operation provides :
 *  - registration of system counters
 *  - module fully initialized
 */
INIT_OP_DECLARE (syscnt_setup);

#endif