ltt-event-header.c

   1 /*
   2  * ltt/ltt-event-header.c
   3  *
   4  * (C) Copyright 2010 - Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
   5  *
   6  * LTTng event header.
   7  *
   8  * Author:
   9  *      Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
  10  *
  11  * Dual LGPL v2.1/GPL v2 license.
  12  */
  13
  14 #include <linux/module.h>
  15
  16 #include "ltt-tracer.h"
  17 #include "ltt-relay.h"
  18
  19 size_t ltt_write_event_header_slow(struct ltt_chanbuf_alloc *bufa,
  20                                    struct ltt_chan_alloc *chana,
  21                                    long buf_offset, u16 eID, u32 event_size,
  22                                    u64 tsc, unsigned int rflags)
  23 {
  24         struct ltt_event_header header;
  25         u16 small_size;
  26
  27         switch (rflags) {
  28         case LTT_RFLAG_ID_SIZE_TSC:
  29                 header.id_time = 29 << LTT_TSC_BITS;
  30                 break;
  31         case LTT_RFLAG_ID_SIZE:
  32                 header.id_time = 30 << LTT_TSC_BITS;
  33                 break;
  34         case LTT_RFLAG_ID:
  35                 header.id_time = 31 << LTT_TSC_BITS;
  36                 break;
  37         default:
  38                 WARN_ON_ONCE(1);
  39                 header.id_time = 0;
  40         }
  41
  42         header.id_time |= (u32)tsc & LTT_TSC_MASK;
  43         ltt_relay_write(bufa, chana, buf_offset, &header, sizeof(header));
  44         buf_offset += sizeof(header);
  45
  46         switch (rflags) {
  47         case LTT_RFLAG_ID_SIZE_TSC:
  48                 small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE);
  49                 ltt_relay_write(bufa, chana, buf_offset,
  50                         &eID, sizeof(u16));
  51                 buf_offset += sizeof(u16);
  52                 ltt_relay_write(bufa, chana, buf_offset,
  53                         &small_size, sizeof(u16));
  54                 buf_offset += sizeof(u16);
  55                 if (small_size == LTT_MAX_SMALL_SIZE) {
  56                         ltt_relay_write(bufa, chana, buf_offset,
  57                                 &event_size, sizeof(u32));
  58                         buf_offset += sizeof(u32);
  59                 }
  60                 buf_offset += ltt_align(buf_offset, sizeof(u64));
  61                 ltt_relay_write(bufa, chana, buf_offset,
  62                         &tsc, sizeof(u64));
  63                 buf_offset += sizeof(u64);
  64                 break;
  65         case LTT_RFLAG_ID_SIZE:
  66                 small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE);
  67                 ltt_relay_write(bufa, chana, buf_offset,
  68                         &eID, sizeof(u16));
  69                 buf_offset += sizeof(u16);
  70                 ltt_relay_write(bufa, chana, buf_offset,
  71                         &small_size, sizeof(u16));
  72                 buf_offset += sizeof(u16);
  73                 if (small_size == LTT_MAX_SMALL_SIZE) {
  74                         ltt_relay_write(bufa, chana, buf_offset,
  75                                 &event_size, sizeof(u32));
  76                         buf_offset += sizeof(u32);
  77                 }
  78                 break;
  79         case LTT_RFLAG_ID:
  80                 ltt_relay_write(bufa, chana, buf_offset,
  81                         &eID, sizeof(u16));
  82                 buf_offset += sizeof(u16);
  83                 break;
  84         }
  85
  86         return buf_offset;
  87 }
  88 EXPORT_SYMBOL_GPL(ltt_write_event_header_slow);
  89
  90 MODULE_LICENSE("GPL and additional rights");
  91 MODULE_AUTHOR("Mathieu Desnoyers");
  92 MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Event Header");