4e079d241f5392d05aee65acdfe5ca3375fd0b07
[lttng-tools.git] / include / lttng-share.h
1 /*
2 * Copyright (C) - 2011 - David Goulet <david.goulet@polymtl.ca>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; only version 2
7 * of the License.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */
18
19 #ifndef _LTTNG_SHARE_H
20 #define _LTTNG_SHARE_H
21
22 /* Default channel attributes */
23 #define DEFAULT_CHANNEL_NAME "channel0"
24 #define DEFAULT_CHANNEL_OVERWRITE 0 /* usec */
25 /* DEFAULT_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
26 #define DEFAULT_CHANNEL_SUBBUF_SIZE 4096 /* bytes */
27 /* DEFAULT_CHANNEL_SUBBUF_NUM must always be a power of 2 */
28 #define DEFAULT_CHANNEL_SUBBUF_NUM 8
29 #define DEFAULT_CHANNEL_SWITCH_TIMER 0 /* usec */
30 #define DEFAULT_CHANNEL_READ_TIMER 200 /* usec */
31 #define DEFAULT_CHANNEL_OUTPUT LTTNG_EVENT_MMAP
32
33 #define DEFAULT_METADATA_SUBBUF_SIZE 4096
34 #define DEFAULT_METADATA_SUBBUF_NUM 2
35
36 /* Kernel has different defaults */
37
38 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
39 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE 262144 /* bytes */
40 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM must always be a power of 2 */
41 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM 4
42 /* See lttng-kernel.h enum lttng_kernel_output for channel output */
43 #define DEFAULT_KERNEL_CHANNEL_OUTPUT LTTNG_EVENT_SPLICE
44
45 /*
46 * Takes a pointer x and transform it so we can use it to access members
47 * without a function call. Here an example:
48 *
49 * #define GET_SIZE(x) LTTNG_REF(x)->size
50 *
51 * struct { int size; } s;
52 *
53 * printf("size : %d\n", GET_SIZE(&s));
54 *
55 * For this example we can't use something like this for compatibility purpose
56 * since this will fail:
57 *
58 * #define GET_SIZE(x) x->size;
59 *
60 * This is mostly use for the compatibility layer of lttng-tools. See
61 * poll/epoll for a good real example. Since x can be on the stack or allocated
62 * memory using malloc(), we must use generic accessors for compat in order to
63 * *not* use a function to access members.
64 */
65 #define LTTNG_REF(x) ((typeof(*x) *)(x))
66
67 /*
68 * Memory allocation zeroed
69 */
70 #define zmalloc(x) calloc(1, x)
71
72 #endif /* _LTTNG_SHARE_H */
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