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construct/include/ircd/prof/scope_cycles.h
2019-09-21 12:15:31 -07:00

63 lines
1.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_PROF_SCOPE_CYCLES_H
namespace ircd::prof
{
struct scope_cycles;
}
/// Count the reference cycles for a scope using the lifetime of this object.
/// The result is stored in `result`. Note that `result` is also used while
/// this object is operating.
struct ircd::prof::scope_cycles
{
uint64_t &result;
scope_cycles(uint64_t &result) noexcept;
~scope_cycles() noexcept;
};
extern inline
__attribute__((flatten, always_inline, gnu_inline, artificial))
ircd::prof::scope_cycles::scope_cycles(uint64_t &result)
noexcept
:result{result}
{
#if defined(__x86_64__) || defined(__i386__)
asm volatile ("mfence");
asm volatile ("lfence");
#endif
result = cycles();
#if defined(__x86_64__) || defined(__i386__)
asm volatile ("lfence");
#endif
}
extern inline
__attribute__((flatten, always_inline, gnu_inline, artificial))
ircd::prof::scope_cycles::~scope_cycles()
noexcept
{
#if defined(__x86_64__) || defined(__i386__)
asm volatile ("mfence");
asm volatile ("lfence");
#endif
result = cycles() - result;
#if defined(__x86_64__) || defined(__i386__)
asm volatile ("lfence");
#endif
}