ltt-ring-buffer-client.h

   1 /*
   2  * ltt-ring-buffer-client.h
   3  *
   4  * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  *
   8  * Dual LGPL v2.1/GPL v2 license.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/trace-clock.h>
  14 #include "ltt-events.h"
  15 #include "ltt-tracer.h"
  16
  17 static const struct lib_ring_buffer_config client_config;
  18
  19 static u64 client_ring_buffer_clock_read(struct channel *chan)
  20 {
  21         return lib_ring_buffer_clock_read(chan);
  22 }
  23
  24 static
  25 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  26                                  struct channel *chan, size_t offset,
  27                                  size_t data_size,
  28                                  size_t *pre_header_padding,
  29                                  unsigned int rflags,
  30                                  struct lib_ring_buffer_ctx *ctx)
  31 {
  32         return record_header_size(config, chan, offset, data_size,
  33                                   pre_header_padding, rflags, ctx);
  34 }
  35
  36 /**
  37  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  38  *
  39  * Return header size without padding after the structure. Don't use packed
  40  * structure because gcc generates inefficient code on some architectures
  41  * (powerpc, mips..)
  42  */
  43 static size_t client_packet_header_size(void)
  44 {
  45         return offsetof(struct packet_header, header_end);
  46 }
  47
  48 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  49                                 unsigned int subbuf_idx)
  50 {
  51         struct channel *chan = buf->backend.chan;
  52         struct packet_header *header =
  53                 (struct packet_header *)
  54                         lib_ring_buffer_offset_address(&buf->backend,
  55                                 subbuf_idx * chan->backend.subbuf_size);
  56
  57         header->timestamp_begin = tsc;
  58         header->content_size = 0xFFFFFFFF; /* for debugging */
  59         write_trace_header(&client_config, header);
  60 }
  61
  62 /*
  63  * offset is assumed to never be 0 here : never deliver a completely empty
  64  * subbuffer. data_size is between 1 and subbuf_size.
  65  */
  66 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
  67                               unsigned int subbuf_idx, unsigned long data_size)
  68 {
  69         struct channel *chan = buf->backend.chan;
  70         struct packet_header *header =
  71                 (struct packet_header *)
  72                         lib_ring_buffer_offset_address(&buf->backend,
  73                                 subbuf_idx * chan->backend.subbuf_size);
  74         unsigned long records_lost = 0;
  75
  76         header->content_size = data_size;
  77         header->packet_size = PAGE_ALIGN(data_size);
  78         header->timestamp_end = tsc;
  79         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
  80         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
  81         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
  82         header->events_lost = records_lost;
  83 }
  84
  85 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
  86                                 int cpu, const char *name)
  87 {
  88         return 0;
  89 }
  90
  91 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
  92 {
  93 }
  94
  95 static const struct lib_ring_buffer_config client_config = {
  96         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
  97         .cb.record_header_size = client_record_header_size,
  98         .cb.subbuffer_header_size = client_packet_header_size,
  99         .cb.buffer_begin = client_buffer_begin,
 100         .cb.buffer_end = client_buffer_end,
 101         .cb.buffer_create = client_buffer_create,
 102         .cb.buffer_finalize = client_buffer_finalize,
 103
 104         .tsc_bits = 32,
 105         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 106         .sync = RING_BUFFER_SYNC_PER_CPU,
 107         .mode = RING_BUFFER_MODE_TEMPLATE,
 108 #ifdef RING_BUFFER_ALIGN
 109         .align = RING_BUFFER_NATURAL,
 110 #else
 111         .align = RING_BUFFER_PACKED,
 112 #endif
 113         .backend = RING_BUFFER_PAGE,
 114         .output = RING_BUFFER_SPLICE,
 115         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 116         .ipi = RING_BUFFER_IPI_BARRIER,
 117         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 118 };
 119
 120 static
 121 struct channel *_channel_create(const char *name,
 122                                 struct ltt_session *session, void *buf_addr,
 123                                 size_t subbuf_size, size_t num_subbuf,
 124                                 unsigned int switch_timer_interval,
 125                                 unsigned int read_timer_interval)
 126 {
 127         return channel_create(&client_config, name, session, buf_addr,
 128                               subbuf_size, num_subbuf, switch_timer_interval,
 129                               read_timer_interval);
 130 }
 131
 132 static
 133 void ltt_channel_destroy(struct channel *chan)
 134 {
 135         channel_destroy(chan);
 136 }
 137
 138 static
 139 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 140 {
 141         struct lib_ring_buffer *buf;
 142         int cpu;
 143
 144         for_each_channel_cpu(cpu, chan) {
 145                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 146                 if (!lib_ring_buffer_open_read(buf))
 147                         return buf;
 148         }
 149         return NULL;
 150 }
 151
 152 static
 153 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 154 {
 155         lib_ring_buffer_release_read(buf);
 156
 157 }
 158
 159 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx)
 160 {
 161         int ret, cpu;
 162
 163         cpu = lib_ring_buffer_get_cpu(&client_config);
 164         if (cpu < 0)
 165                 return -EPERM;
 166         ctx->cpu = cpu;
 167
 168         ret = lib_ring_buffer_reserve(&client_config, ctx);
 169         if (ret)
 170                 goto put;
 171         return ret;
 172
 173 put:
 174         lib_ring_buffer_put_cpu(&client_config);
 175         return ret;
 176 }
 177
 178 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 179 {
 180         lib_ring_buffer_commit(&client_config, ctx);
 181         lib_ring_buffer_put_cpu(&client_config);
 182 }
 183
 184
 185 static struct ltt_transport ltt_relay_transport = {
 186         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 187         .owner = THIS_MODULE,
 188         .ops = {
 189                 .channel_create = _channel_create,
 190                 .channel_destroy = ltt_channel_destroy,
 191                 .buffer_read_open = ltt_buffer_read_open,
 192                 .buffer_read_close = ltt_buffer_read_close,
 193                 .event_reserve = ltt_event_reserve,
 194                 .event_commit = ltt_event_commit,
 195         },
 196 };
 197
 198 static int __init ltt_ring_buffer_client_init(void)
 199 {
 200         printk(KERN_INFO "LTT : ltt ring buffer client init\n");
 201         ltt_transport_register(&ltt_relay_transport);
 202         return 0;
 203 }
 204
 205 module_init(ltt_ring_buffer_client_init);
 206
 207 static void __exit ltt_ring_buffer_client_exit(void)
 208 {
 209         printk(KERN_INFO "LTT : ltt ring buffer client exit\n");
 210         ltt_transport_unregister(&ltt_relay_transport);
 211 }
 212
 213 module_exit(ltt_ring_buffer_client_exit);
 214
 215 MODULE_LICENSE("GPL and additional rights");
 216 MODULE_AUTHOR("Mathieu Desnoyers");
 217 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 218                    " client");