mirror of
https://github.com/matrix-construct/construct
synced 2024-10-30 02:18:58 +01:00
55 lines
1.6 KiB
C++
55 lines
1.6 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_SYSCALL_TIMER_H
|
|
|
|
namespace ircd::prof
|
|
{
|
|
struct syscall_timer;
|
|
}
|
|
|
|
/// This suite of devices is intended to figure out when a system call is
|
|
/// really slow or "blocking." The original use-case is for io_submit() in
|
|
/// fs::aio.
|
|
///
|
|
/// The sample is conducted with times(2) which is itself a system call
|
|
/// though reasonably fast, and the result has poor resolution meaning
|
|
/// the result of at() is generally 0 unless the system call was very slow.
|
|
///
|
|
/// It is started on construction. The user must later call sample()
|
|
/// which returns the value of at() as well.
|
|
struct ircd::prof::syscall_timer
|
|
{
|
|
struct high_resolution;
|
|
|
|
uint64_t started, stopped;
|
|
|
|
public:
|
|
uint64_t at() const;
|
|
uint64_t sample();
|
|
|
|
syscall_timer() noexcept;
|
|
};
|
|
|
|
/// This is a higher resolution alternative. The sample may be conducted
|
|
/// with getrusage() or perf events; the exact method is TBD and may be
|
|
/// expensive/intrusive. This device should be used temporarily by developers
|
|
/// and not left in place in committed code.
|
|
struct ircd::prof::syscall_timer::high_resolution
|
|
{
|
|
uint64_t started, stopped;
|
|
|
|
public:
|
|
uint64_t at() const;
|
|
uint64_t sample();
|
|
|
|
high_resolution() noexcept;
|
|
};
|