aboutsummaryrefslogtreecommitdiffstats
path: root/include/litmus/affinity.h
blob: 5eee0eaa170d32b6102b3d3ed0328b318fc4b187 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
#ifndef __LITMUS_AFFINITY_H
#define __LITMUS_AFFINITY_H

#include <linux/cpumask.h>

/*
  L1 (instr) = depth 0
  L1 (data)  = depth 1
  L2 = depth 2
  L3 = depth 3
 */
#define NUM_CACHE_LEVELS 4

struct neighborhood
{
	unsigned int size[NUM_CACHE_LEVELS];
	cpumask_var_t neighbors[NUM_CACHE_LEVELS];
};

/* topology info is stored redundently in a big array for fast lookups */
extern struct neighborhood neigh_info[NR_CPUS];

void init_topology(void); /* called by Litmus module's _init_litmus() */

/* Works like:
void get_nearest_available_cpu(
	cpu_entry_t* nearest,
	cpu_entry_t* start,
	cpu_entry_t* entries,
	int release_master)

Set release_master = -1 for no RM.

We use a macro here to exploit the fact that C-EDF and G-EDF
have similar structures for their cpu_entry_t structs, even though
they do not share a common base-struct.  The macro allows us to
avoid code duplication.

TODO: Factor out the job-to-processor linking from C/G-EDF into
a reusable "processor mapping".  (See B.B.'s RTSS'09 paper &
dissertation.)
 */
#define get_nearest_available_cpu(nearest, start, entries, release_master) \
{ \
	(nearest) = NULL; \
	if (!(start)->linked) { \
		(nearest) = (start); \
	} else { \
		int __level; \
		int __cpu; \
		struct neighborhood* __neighbors = &neigh_info[(start)->cpu]; \
		\
		for (__level = 0; (__level < NUM_CACHE_LEVELS) && !(nearest); ++__level) { \
			if (__neighbors->size[__level] > 1) { \
				for_each_cpu(__cpu, __neighbors->neighbors[__level]) { \
					if (__cpu != (release_master)) { \
						cpu_entry_t* __entry = &per_cpu((entries), __cpu); \
						if (!__entry->linked) { \
							(nearest) = __entry; \
							break; \
						} \
					} \
				} \
			} else if (__neighbors->size[__level] == 0) { \
				break; \
			} \
		} \
	} \
	\
	if ((nearest)) { \
		TRACE("P%d is closest available CPU to P%d\n", \
				(nearest)->cpu, (start)->cpu); \
	} else { \
		TRACE("Could not find an available CPU close to P%d\n", \
				(start)->cpu); \
	} \
}

#endif