src/common/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 /* Default size of a hash table */
  25 #define DEFAULT_HT_SIZE                 4
  26
  27 /* Default channel attributes */
  28 #define DEFAULT_CHANNEL_NAME            "channel0"
  29 #define DEFAULT_CHANNEL_OVERWRITE       0       /* usec */
  30 /* DEFAULT_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
  31 #define DEFAULT_CHANNEL_SUBBUF_SIZE     4096    /* bytes */
  32 /* DEFAULT_CHANNEL_SUBBUF_NUM must always be a power of 2 */
  33 #define DEFAULT_CHANNEL_SUBBUF_NUM      8
  34 #define DEFAULT_CHANNEL_SWITCH_TIMER    0       /* usec */
  35 #define DEFAULT_CHANNEL_READ_TIMER              200     /* usec */
  36 #define DEFAULT_CHANNEL_OUTPUT          LTTNG_EVENT_MMAP
  37
  38 #define DEFAULT_METADATA_SUBBUF_SIZE    4096
  39 #define DEFAULT_METADATA_SUBBUF_NUM     2
  40
  41 /* Kernel has different defaults */
  42
  43 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE must always be a power of 2 */
  44 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_SIZE  262144    /* bytes */
  45 /* DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM must always be a power of 2 */
  46 #define DEFAULT_KERNEL_CHANNEL_SUBBUF_NUM   4
  47 /* See lttng-kernel.h enum lttng_kernel_output for channel output */
  48 #define DEFAULT_KERNEL_CHANNEL_OUTPUT       LTTNG_EVENT_SPLICE
  49
  50 /* User space defaults */
  51
  52 /* Must be a power of 2 */
  53 #define DEFAULT_UST_CHANNEL_SUBBUF_SIZE     4096    /* bytes */
  54 /* Must be a power of 2 */
  55 #define DEFAULT_UST_CHANNEL_SUBBUF_NUM      4
  56 /* See lttng-ust.h enum lttng_ust_output */
  57 #define DEFAULT_UST_CHANNEL_OUTPUT          LTTNG_EVENT_MMAP
  58
  59 /*
  60  * Default timeout value for the sem_timedwait() call. Blocking forever is not
  61  * wanted so a timeout is used to control the data flow and not freeze the
  62  * session daemon.
  63  */
  64 #define DEFAULT_SEM_WAIT_TIMEOUT            30    /* in seconds */
  65
  66 /*
  67  * Takes a pointer x and transform it so we can use it to access members
  68  * without a function call. Here an example:
  69  *
  70  *    #define GET_SIZE(x) LTTNG_REF(x)->size
  71  *
  72  *    struct { int size; } s;
  73  *
  74  *    printf("size : %d\n", GET_SIZE(&s));
  75  *
  76  * For this example we can't use something like this for compatibility purpose
  77  * since this will fail:
  78  *
  79  *    #define GET_SIZE(x) x->size;
  80  *
  81  * This is mostly use for the compatibility layer of lttng-tools. See
  82  * poll/epoll for a good example. Since x can be on the stack or allocated
  83  * memory using malloc(), we must use generic accessors for compat in order to
  84  * *not* use a function to access members and not the variable name.
  85  */
  86 #define LTTNG_REF(x) ((typeof(*x) *)(x))
  87
  88 /*
  89  * Memory allocation zeroed
  90  */
  91 #define zmalloc(x) calloc(1, x)
  92
  93 #ifndef ARRAY_SIZE
  94 #define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
  95 #endif
  96
  97
  98 #endif /* _LTTNG_SHARE_H */