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 "wrapper/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         .backend = RING_BUFFER_PAGE,
 109         .output = RING_BUFFER_SPLICE,
 110         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 111         .ipi = RING_BUFFER_IPI_BARRIER,
 112         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 113 };
 114
 115 static
 116 struct channel *_channel_create(const char *name,
 117                                 struct ltt_session *session, void *buf_addr,
 118                                 size_t subbuf_size, size_t num_subbuf,
 119                                 unsigned int switch_timer_interval,
 120                                 unsigned int read_timer_interval)
 121 {
 122         return channel_create(&client_config, name, session, buf_addr,
 123                               subbuf_size, num_subbuf, switch_timer_interval,
 124                               read_timer_interval);
 125 }
 126
 127 static
 128 void ltt_channel_destroy(struct channel *chan)
 129 {
 130         channel_destroy(chan);
 131 }
 132
 133 static
 134 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 135 {
 136         struct lib_ring_buffer *buf;
 137         int cpu;
 138
 139         for_each_channel_cpu(cpu, chan) {
 140                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 141                 if (!lib_ring_buffer_open_read(buf))
 142                         return buf;
 143         }
 144         return NULL;
 145 }
 146
 147 static
 148 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 149 {
 150         lib_ring_buffer_release_read(buf);
 151
 152 }
 153
 154 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx)
 155 {
 156         int ret, cpu;
 157
 158         cpu = lib_ring_buffer_get_cpu(&client_config);
 159         if (cpu < 0)
 160                 return -EPERM;
 161         ctx->cpu = cpu;
 162
 163         ret = lib_ring_buffer_reserve(&client_config, ctx);
 164         if (ret)
 165                 goto put;
 166         return ret;
 167
 168 put:
 169         lib_ring_buffer_put_cpu(&client_config);
 170         return ret;
 171 }
 172
 173 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 174 {
 175         lib_ring_buffer_commit(&client_config, ctx);
 176         lib_ring_buffer_put_cpu(&client_config);
 177 }
 178
 179 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 180                      size_t len)
 181 {
 182         lib_ring_buffer_write(&client_config, ctx, src, len);
 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                 .event_write = ltt_event_write,
 196         },
 197 };
 198
 199 static int __init ltt_ring_buffer_client_init(void)
 200 {
 201         printk(KERN_INFO "LTT : ltt ring buffer client init\n");
 202         ltt_transport_register(&ltt_relay_transport);
 203         return 0;
 204 }
 205
 206 module_init(ltt_ring_buffer_client_init);
 207
 208 static void __exit ltt_ring_buffer_client_exit(void)
 209 {
 210         printk(KERN_INFO "LTT : ltt ring buffer client exit\n");
 211         ltt_transport_unregister(&ltt_relay_transport);
 212 }
 213
 214 module_exit(ltt_ring_buffer_client_exit);
 215
 216 MODULE_LICENSE("GPL and additional rights");
 217 MODULE_AUTHOR("Mathieu Desnoyers");
 218 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 219                    " client");