scx_rusty 1.0.19

A multi-domain, BPF / user space hybrid scheduler used within sched_ext, which is a Linux kernel feature which enables implementing kernel thread schedulers in BPF and dynamically loading them. https://github.com/sched-ext/scx/tree/main
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// Copyright (c) Meta Platforms, Inc. and affiliates.

// This software may be used and distributed according to the terms of the
// GNU General Public License version 2.
#ifndef __INTF_H
#define __INTF_H

#include <stdbool.h>
#ifndef __kptr
#ifdef __KERNEL__
#error "__kptr_ref not defined in the kernel"
#endif
#define __kptr
#endif

#ifndef __KERNEL__
typedef unsigned char u8;
typedef unsigned int u32;
typedef unsigned long long u64;
#endif

#ifdef LSP
#define __bpf__
#include "../../../../include/scx/ravg.bpf.h"
#else
#include <scx/ravg.bpf.h>
#endif

enum consts {
	MAX_CPUS		= 512,
	MAX_DOMS		= 64,	/* limited to avoid complex bitmask ops */
	MAX_NUMA_NODES		= MAX_DOMS,	/* Assume at least 1 domain per NUMA node */
	CACHELINE_SIZE		= 64,
	NO_DOM_FOUND		= MAX_DOMS + 1,

	LB_DEFAULT_WEIGHT	= 100,
	LB_MIN_WEIGHT		= 1,
	LB_MAX_WEIGHT		= 10000,
	LB_LOAD_BUCKETS		= 100,	/* Must be a factor of LB_MAX_WEIGHT */
	LB_WEIGHT_PER_BUCKET	= LB_MAX_WEIGHT / LB_LOAD_BUCKETS,

	/* Time constants */
	MSEC_PER_SEC		= 1000LLU,
	USEC_PER_MSEC		= 1000LLU,
	NSEC_PER_USEC		= 1000LLU,
	NSEC_PER_MSEC           = USEC_PER_MSEC * NSEC_PER_USEC,
	USEC_PER_SEC            = USEC_PER_MSEC * MSEC_PER_SEC,
	NSEC_PER_SEC            = NSEC_PER_USEC * USEC_PER_SEC,

	/* Constants used for determining a task's deadline */
	DL_RUNTIME_SCALE	= 2, /* roughly scales average runtime to */
				     /* same order of magnitude as waker  */
				     /* and blocked frequencies */
	DL_MAX_LATENCY_NS	= (50 * NSEC_PER_MSEC),
	DL_FREQ_FT_MAX		= 100000,
	DL_MAX_LAT_PRIO		= 39,

	/*
	 * When userspace load balancer is trying to determine the tasks to push
	 * out from an overloaded domain, it looks at the the following number
	 * of recently active tasks of the domain. While this may lead to
	 * spurious migration victim selection failures in pathological cases,
	 * this isn't a practical problem as the LB rounds are best-effort
	 * anyway and will be retried until loads are balanced.
	 */
	MAX_DOM_ACTIVE_TPTRS	= 1024,

	STATIC_ALLOC_PAGES_GRANULARITY = 1,
};

/* Statistics */
enum stat_idx {
	/* The following fields add up to all dispatched tasks */
	RUSTY_STAT_WAKE_SYNC,
	RUSTY_STAT_SYNC_PREV_IDLE,
	RUSTY_STAT_PREV_IDLE,
	RUSTY_STAT_GREEDY_IDLE,
	RUSTY_STAT_PINNED,
	RUSTY_STAT_DIRECT_DISPATCH,
	RUSTY_STAT_DIRECT_GREEDY,
	RUSTY_STAT_DIRECT_GREEDY_FAR,
	RUSTY_STAT_DSQ_DISPATCH,
	RUSTY_STAT_GREEDY_LOCAL,
	RUSTY_STAT_GREEDY_XNUMA,

	/* Extra stats that don't contribute to total */
	RUSTY_STAT_REPATRIATE,
	RUSTY_STAT_KICK_GREEDY,
	RUSTY_STAT_LOAD_BALANCE,

	/* Errors */
	RUSTY_STAT_TASK_GET_ERR,

	/* Deadline related stats */
	RUSTY_STAT_DL_CLAMP,
	RUSTY_STAT_DL_PRESET,

	RUSTY_NR_STATS,
};

#endif /* __INTF_H */