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construct/include/ircd/gpt/task.h
2021-04-22 12:27:57 -07:00

116 lines
3.8 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2021 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_GPT_TASK_H
/// Task Control Page
///
/// The control block is shared with our device software. Execution state is
/// maintained in the task control block across cycles. The control block is
/// the mutable state component for an execution; for the immutable component
/// also shared with device software see opts.h.
///
struct ircd_gpt_task
{
/// Header magic 0xC7012C70
uint magic;
/// Hypercall code set by our device software upon completion and control
/// transfer back to the host. Negative codes indicate errors, positive
/// codes are used for status and/or procedure calls; zero is also an error.
enum ircd_gpt_hypercall call;
/// Token ring head. Tokens in the ring extend behind the head for
/// `tokens`. The `head` value is automatically modulated by device
/// software to wrap around the ring.
uint head;
/// Token counter. The counter indicates the number of valid tokens in
/// the context buffer. This value must not exceed the buffer size.
uint tokens;
/// Accumulates the number of task cycles. The cycle counter is incremented
/// by device software after each repetition of the kernel pipeline to
/// produce one additional token.
ulong cycle;
/// Accumulates the epoch count for the task. The counter is incremented
/// by one in device software before control returns back to the host.
/// Several cycles may occur during each epoch.
ulong epoch;
/// Accumulates the number of tokens produced by the task. Several tokens
/// may be produced each epoch, but currently only one token is produced
/// each cycle.
ulong produced;
/// Accumulates the number tokens witnessed by the task. The number of
/// tokens in the context for each cycle is counted as witnessed.
ulong witnessed;
/// Accumulates time in microseconds elapsed for the task.
ulong elapsed;
/// PRNG xoshiro256 state. This is the de facto random seed which can be
/// set before cycle entry by the host. It is updated by device software
/// when used.
ulong rand[4];
/// Updated by the host with the value of the timestamp register as sampled
/// immediately before each transfer of control to the device.
ulong host_tsc;
/// State counters for the accept/error sequence codes.
uint accept_seq[4], error_seq[4];
/// The token buffer starts at offset 2048 and continues to the end of
/// the page; options specify the size of the tokens buffer in tokens.
/// Additional pages must be attached for larger buffer sizes.
ushort token[] __attribute__((aligned(2048)));
}
__attribute__((aligned(4096)));
#ifdef __cplusplus
/// Task Context
///
/// State for a task.
struct ircd::gpt::task
{
enum status :char;
/// Reference to the attached options.
const gpt::opts *opts {nullptr};
/// Reference to control pages.
struct ircd_gpt_task *ctrl {nullptr};
/// Current task status.
enum status status {'\0'};
task(const gpt::opts * = nullptr,
struct ircd_gpt_task * = nullptr);
~task() noexcept;
};
/// The current status of a task is indicated with intelligible characters
enum ircd::gpt::task::status
:char
{
QUEUED = 'Q', ///< Queued for execution.
RUNNING = 'R', ///< Currently being executed.
ACCEPT = 'A', ///< Execution completed successfully.
ERROR = 'E', ///< Execution did not complete successfully.
};
static_assert(sizeof(struct ircd_gpt_task) == 4096);
static_assert(std::is_standard_layout<struct ircd_gpt_task>::value);
#endif