libust/channels.h

   1 #ifndef UST_CHANNELS_H
   2 #define UST_CHANNELS_H
   3
   4 /*
   5  * Copyright (C) 2008 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   6  *
   7  * Dynamic tracer channel allocation.
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #include <linux/limits.h>
  25 #include <errno.h>
  26 #include <ust/kcompat/kcompat.h>
  27 #include <urcu/list.h>
  28 #include <ust/core.h>
  29
  30 #define EVENTS_PER_CHANNEL      65536
  31 #define MAX_CPUS                32
  32
  33 struct ust_trace;
  34
  35 struct ust_buffer;
  36
  37 struct ust_channel {
  38         /* First 32 bytes cache-hot cacheline */
  39         struct ust_trace *trace;
  40         int *buf_struct_shmids;
  41         struct ust_buffer **buf;
  42         int overwrite:1;
  43         /* whether collection is requested upon trace start */
  44         int request_collection:1;
  45         int active:1;
  46         unsigned int n_subbufs_order;
  47         unsigned long commit_count_mask;        /*
  48                                                  * Commit count mask, removing
  49                                                  * the MSBs corresponding to
  50                                                  * bits used to represent the
  51                                                  * subbuffer index.
  52                                                  */
  53         /* End of first 32 bytes cacheline */
  54
  55         struct kref kref;       /* Channel transport reference count */
  56         size_t subbuf_size;
  57         int subbuf_size_order;
  58         unsigned int subbuf_cnt;
  59         const char *channel_name;
  60         int n_cpus;
  61
  62         u32 version;
  63         size_t alloc_size;
  64         struct cds_list_head list;
  65 } ____cacheline_aligned;
  66
  67 struct ltt_channel_setting {
  68         unsigned int subbuf_size;
  69         unsigned int subbuf_cnt;
  70         struct kref kref;       /* Number of references to structure content */
  71         struct cds_list_head list;
  72         unsigned int index;     /* index of channel in trace channel array */
  73         u16 free_event_id;      /* Next event ID to allocate */
  74         char name[PATH_MAX];
  75 };
  76
  77 extern int ltt_channels_register(const char *name);
  78 extern int ltt_channels_unregister(const char *name);
  79 extern int ltt_channels_set_default(const char *name,
  80                              unsigned int subbuf_size,
  81                              unsigned int subbuf_cnt);
  82 extern const char *ltt_channels_get_name_from_index(unsigned int index);
  83 extern int ltt_channels_get_index_from_name(const char *name);
  84 extern struct ust_channel *ltt_channels_trace_alloc(unsigned int *nr_channels,
  85                                                     int overwrite,
  86                                                     int request_collection,
  87                                                     int active);
  88 extern void ltt_channels_trace_free(struct ust_channel *channels);
  89 extern int _ltt_channels_get_event_id(const char *channel, const char *name);
  90 extern int ltt_channels_get_event_id(const char *channel, const char *name);
  91
  92 extern int ust_channels_overwrite_by_default;
  93 extern int ust_channels_request_collection_by_default;
  94
  95 #endif /* UST_CHANNELS_H */