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