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
  27 #include <ust/kernelcompat.h>
  28
  29 #define EVENTS_PER_CHANNEL      65536
  30 #define MAX_CPUS                32
  31
  32 struct ust_trace;
  33
  34 struct ust_buffer;
  35
  36 struct ust_channel {
  37         /* First 32 bytes cache-hot cacheline */
  38         struct ust_trace *trace;
  39         int *buf_struct_shmids;
  40         struct ust_buffer **buf;
  41         int overwrite:1;
  42         /* whether collection is requested upon trace start */
  43         int request_collection:1;
  44         int active:1;
  45         unsigned int n_subbufs_order;
  46         unsigned long commit_count_mask;        /*
  47                                                  * Commit count mask, removing
  48                                                  * the MSBs corresponding to
  49                                                  * bits used to represent the
  50                                                  * subbuffer index.
  51                                                  */
  52         /* End of first 32 bytes cacheline */
  53
  54         struct kref kref;       /* Channel transport reference count */
  55         size_t subbuf_size;
  56         int subbuf_size_order;
  57         unsigned int subbuf_cnt;
  58         const char *channel_name;
  59         int n_cpus;
  60
  61         u32 version;
  62         size_t alloc_size;
  63         struct list_head list;
  64 } ____cacheline_aligned;
  65
  66 struct ltt_channel_setting {
  67         unsigned int subbuf_size;
  68         unsigned int subbuf_cnt;
  69         struct kref kref;       /* Number of references to structure content */
  70         struct list_head list;
  71         unsigned int index;     /* index of channel in trace channel array */
  72         u16 free_event_id;      /* Next event ID to allocate */
  73         char name[PATH_MAX];
  74 };
  75
  76 extern int ltt_channels_register(const char *name);
  77 extern int ltt_channels_unregister(const char *name);
  78 extern int ltt_channels_set_default(const char *name,
  79                              unsigned int subbuf_size,
  80                              unsigned int subbuf_cnt);
  81 extern const char *ltt_channels_get_name_from_index(unsigned int index);
  82 extern int ltt_channels_get_index_from_name(const char *name);
  83 extern struct ust_channel *ltt_channels_trace_alloc(unsigned int *nr_channels,
  84                                                     int overwrite,
  85                                                     int request_collection,
  86                                                     int active);
  87 extern void ltt_channels_trace_free(struct ust_channel *channels);
  88 extern int _ltt_channels_get_event_id(const char *channel, const char *name);
  89 extern int ltt_channels_get_event_id(const char *channel, const char *name);
  90
  91 extern int ust_channels_overwrite_by_default;
  92 extern int ust_channels_request_collection_by_default;
  93
  94 #endif /* UST_CHANNELS_H */