708a1f009cf3727d54c42ccf2da62557de1d7db2
[lttng-tools.git] / include / lttng-share.h
1 /*
2 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
3 * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation; only version 2 of the License.
8 *
9 * This program is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
16 * Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 #ifndef _LTTNG_SHARE_H
20 #define _LTTNG_SHARE_H
21
22 #include <stdlib.h>
23
24 #include <lttng/lttng.h>
25
26 /* Default size of a hash table */
27 #define DEFAULT_HT_SIZE 32
28
29 /* Default channel attributes */
30 #define DEFAULT_CHANNEL_NAME "channel0"
31 #define DEFAULT_CHANNEL_OVERWRITE 0 /* usec */
32 /* DEFAULT_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
33 #define DEFAULT_CHANNEL_SUBBUF_SIZE 4096 /* bytes */
34 /* DEFAULT_CHANNEL_SUBBUF_NUM must always be a power of 2 */
35 #define DEFAULT_CHANNEL_SUBBUF_NUM 8
36 #define DEFAULT_CHANNEL_SWITCH_TIMER 0 /* usec */
37 #define DEFAULT_CHANNEL_READ_TIMER 200 /* usec */
38 #define DEFAULT_CHANNEL_OUTPUT LTTNG_EVENT_MMAP
39
40 #define DEFAULT_METADATA_SUBBUF_SIZE 4096
41 #define DEFAULT_METADATA_SUBBUF_NUM 2
42
43 /* Kernel has different defaults */
44
45 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
46 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE 262144 /* bytes */
47 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM must always be a power of 2 */
48 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM 4
49 /* See lttng-kernel.h enum lttng_kernel_output for channel output */
50 #define DEFAULT_KERNEL_CHANNEL_OUTPUT LTTNG_EVENT_SPLICE
51
52 /* User space defaults */
53
54 /* Must be a power of 2 */
55 #define DEFAULT_UST_CHANNEL_SUBBUF_SIZE 4096 /* bytes */
56 /* Must be a power of 2 */
57 #define DEFAULT_UST_CHANNEL_SUBBUF_NUM 4
58 /* See lttng-ust.h enum lttng_ust_output */
59 #define DEFAULT_UST_CHANNEL_OUTPUT LTTNG_EVENT_MMAP
60
61 /*
62 * Default timeout value for the sem_timedwait() call. Blocking forever is not
63 * wanted so a timeout is used to control the data flow and not freeze the
64 * session daemon.
65 */
66 #define DEFAULT_SEM_WAIT_TIMEOUT 30 /* in seconds */
67
68 /*
69 * Takes a pointer x and transform it so we can use it to access members
70 * without a function call. Here an example:
71 *
72 * #define GET_SIZE(x) LTTNG_REF(x)->size
73 *
74 * struct { int size; } s;
75 *
76 * printf("size : %d\n", GET_SIZE(&s));
77 *
78 * For this example we can't use something like this for compatibility purpose
79 * since this will fail:
80 *
81 * #define GET_SIZE(x) x->size;
82 *
83 * This is mostly use for the compatibility layer of lttng-tools. See
84 * poll/epoll for a good example. Since x can be on the stack or allocated
85 * memory using malloc(), we must use generic accessors for compat in order to
86 * *not* use a function to access members and not the variable name.
87 */
88 #define LTTNG_REF(x) ((typeof(*x) *)(x))
89
90 /*
91 * Memory allocation zeroed
92 */
93 #define zmalloc(x) calloc(1, x)
94
95 #ifndef ARRAY_SIZE
96 #define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
97 #endif
98
99
100 #endif /* _LTTNG_SHARE_H */
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