summaryrefslogtreecommitdiff
path: root/trace2/tr2_tls.c
blob: 8e65b0361dbedb7360d3d0f30229875faf5088d4 (plain)
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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
#include "cache.h"
#include "thread-utils.h"
#include "trace2/tr2_tls.h"

/*
 * Initialize size of the thread stack for nested regions.
 * This is used to store nested region start times.  Note that
 * this stack is per-thread and not per-trace-key.
 */
#define TR2_REGION_NESTING_INITIAL_SIZE (100)

static struct tr2tls_thread_ctx *tr2tls_thread_main;
static uint64_t tr2tls_us_start_main;

static pthread_mutex_t tr2tls_mutex;
static pthread_key_t tr2tls_key;

static int tr2_next_thread_id; /* modify under lock */

struct tr2tls_thread_ctx *tr2tls_create_self(const char *thread_name)
{
	uint64_t us_now = getnanotime() / 1000;
	struct tr2tls_thread_ctx *ctx = xcalloc(1, sizeof(*ctx));

	/*
	 * Implicitly "tr2tls_push_self()" to capture the thread's start
	 * time in array_us_start[0].  For the main thread this gives us the
	 * application run time.
	 */
	ctx->alloc = TR2_REGION_NESTING_INITIAL_SIZE;
	ctx->array_us_start = (uint64_t *)xcalloc(ctx->alloc, sizeof(uint64_t));
	ctx->array_us_start[ctx->nr_open_regions++] = us_now;

	ctx->thread_id = tr2tls_locked_increment(&tr2_next_thread_id);

	strbuf_init(&ctx->thread_name, 0);
	if (ctx->thread_id)
		strbuf_addf(&ctx->thread_name, "th%02d:", ctx->thread_id);
	strbuf_addstr(&ctx->thread_name, thread_name);
	if (ctx->thread_name.len > TR2_MAX_THREAD_NAME)
		strbuf_setlen(&ctx->thread_name, TR2_MAX_THREAD_NAME);

	pthread_setspecific(tr2tls_key, ctx);

	return ctx;
}

struct tr2tls_thread_ctx *tr2tls_get_self(void)
{
	struct tr2tls_thread_ctx *ctx = pthread_getspecific(tr2tls_key);

	/*
	 * If the thread-proc did not call trace2_thread_start(), we won't
	 * have any TLS data associated with the current thread.  Fix it
	 * here and silently continue.
	 */
	if (!ctx)
		ctx = tr2tls_create_self("unknown");

	return ctx;
}

int tr2tls_is_main_thread(void)
{
	struct tr2tls_thread_ctx *ctx = pthread_getspecific(tr2tls_key);

	return ctx == tr2tls_thread_main;
}

void tr2tls_unset_self(void)
{
	struct tr2tls_thread_ctx *ctx;

	ctx = tr2tls_get_self();

	pthread_setspecific(tr2tls_key, NULL);

	free(ctx->array_us_start);
	free(ctx);
}

void tr2tls_push_self(uint64_t us_now)
{
	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();

	ALLOC_GROW(ctx->array_us_start, ctx->nr_open_regions + 1, ctx->alloc);
	ctx->array_us_start[ctx->nr_open_regions++] = us_now;
}

void tr2tls_pop_self(void)
{
	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();

	if (!ctx->nr_open_regions)
		BUG("no open regions in thread '%s'", ctx->thread_name.buf);

	ctx->nr_open_regions--;
}

void tr2tls_pop_unwind_self(void)
{
	struct tr2tls_thread_ctx *ctx = tr2tls_get_self();

	while (ctx->nr_open_regions > 1)
		tr2tls_pop_self();
}

uint64_t tr2tls_region_elasped_self(uint64_t us)
{
	struct tr2tls_thread_ctx *ctx;
	uint64_t us_start;

	ctx = tr2tls_get_self();
	if (!ctx->nr_open_regions)
		return 0;

	us_start = ctx->array_us_start[ctx->nr_open_regions - 1];

	return us - us_start;
}

uint64_t tr2tls_absolute_elapsed(uint64_t us)
{
	if (!tr2tls_thread_main)
		return 0;

	return us - tr2tls_us_start_main;
}

void tr2tls_init(void)
{
	pthread_key_create(&tr2tls_key, NULL);
	init_recursive_mutex(&tr2tls_mutex);

	tr2tls_thread_main = tr2tls_create_self("main");
	/*
	 * Keep a copy of the absolute start time of the main thread
	 * in a fixed variable since other threads need to access it.
	 * This also eliminates the need to lock accesses to the main
	 * thread's array (because of reallocs).
	 */
	tr2tls_us_start_main = tr2tls_thread_main->array_us_start[0];
}

void tr2tls_release(void)
{
	tr2tls_unset_self();
	tr2tls_thread_main = NULL;

	pthread_mutex_destroy(&tr2tls_mutex);
	pthread_key_delete(tr2tls_key);
}

int tr2tls_locked_increment(int *p)
{
	int current_value;

	pthread_mutex_lock(&tr2tls_mutex);
	current_value = *p;
	*p = current_value + 1;
	pthread_mutex_unlock(&tr2tls_mutex);

	return current_value;
}