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 channel attributes */
  27 #define DEFAULT_CHANNEL_NAME            "channel0"
  28 #define DEFAULT_CHANNEL_OVERWRITE       0       /* usec */
  29 /* DEFAULT_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
  30 #define DEFAULT_CHANNEL_SUBBUF_SIZE     4096    /* bytes */
  31 /* DEFAULT_CHANNEL_SUBBUF_NUM must always be a power of 2 */
  32 #define DEFAULT_CHANNEL_SUBBUF_NUM      8
  33 #define DEFAULT_CHANNEL_SWITCH_TIMER    0       /* usec */
  34 #define DEFAULT_CHANNEL_READ_TIMER              200     /* usec */
  35 #define DEFAULT_CHANNEL_OUTPUT          LTTNG_EVENT_MMAP
  36
  37 #define DEFAULT_METADATA_SUBBUF_SIZE    4096
  38 #define DEFAULT_METADATA_SUBBUF_NUM     2
  39
  40 /* Kernel has different defaults */
  41
  42 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
  43 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE  262144    /* bytes */
  44 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM must always be a power of 2 */
  45 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM   4
  46 /* See lttng-kernel.h enum lttng_kernel_output for channel output */
  47 #define DEFAULT_KERNEL_CHANNEL_OUTPUT       LTTNG_EVENT_SPLICE
  48
  49 /* User space defaults */
  50
  51 /* Must be a power of 2 */
  52 #define DEFAULT_UST_CHANNEL_SUBBUF_SIZE     4096    /* bytes */
  53 /* Must be a power of 2 */
  54 #define DEFAULT_UST_CHANNEL_SUBBUF_NUM      4
  55 /* See lttng-ust.h enum lttng_ust_output */
  56 #define DEFAULT_UST_CHANNEL_OUTPUT          LTTNG_UST_MMAP
  57
  58 /*
  59  * Default timeout value for the sem_timedwait() call. Blocking forever is not
  60  * wanted so a timeout is used to control the data flow and not freeze the
  61  * session daemon.
  62  */
  63 #define DEFAULT_SEM_WAIT_TIMEOUT            30    /* in seconds */
  64
  65 /*
  66  * Takes a pointer x and transform it so we can use it to access members
  67  * without a function call. Here an example:
  68  *
  69  *    #define GET_SIZE(x) LTTNG_REF(x)->size
  70  *
  71  *    struct { int size; } s;
  72  *
  73  *    printf("size : %d\n", GET_SIZE(&s));
  74  *
  75  * For this example we can't use something like this for compatibility purpose
  76  * since this will fail:
  77  *
  78  *    #define GET_SIZE(x) x->size;
  79  *
  80  * This is mostly use for the compatibility layer of lttng-tools. See
  81  * poll/epoll for a good example. Since x can be on the stack or allocated
  82  * memory using malloc(), we must use generic accessors for compat in order to
  83  * *not* use a function to access members and not the variable name.
  84  */
  85 #define LTTNG_REF(x) ((typeof(*x) *)(x))
  86
  87 /*
  88  * Memory allocation zeroed
  89  */
  90 #define zmalloc(x) calloc(1, x)
  91
  92 #ifndef ARRAY_SIZE
  93 #define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
  94 #endif
  95
  96
  97 #endif /* _LTTNG_SHARE_H */