xnu-2782.20.48.tar.gz

[apple/xnu.git] / bsd / sys / dtrace_impl.h

diff --git a/bsd/sys/dtrace_impl.h b/bsd/sys/dtrace_impl.h
index 71dc020f2985b08c34a58cbea9f8e86a9cc287d2..cbb14c0abd651fcade830c0dbb5fff44da1acf20 100644 (file)
--- a/bsd/sys/dtrace_impl.h
+++ b/bsd/sys/dtrace_impl.h
@@ -22,6 +22,8 @@
 /*
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ *
+ * Portions Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 #ifndef _SYS_DTRACE_IMPL_H
@@ -202,15 +204,18 @@ typedef struct dtrace_hash {
  * predicate is non-NULL, the DIF object is executed.  If the result is
  * non-zero, the action list is processed, with each action being executed
  * accordingly.  When the action list has been completely executed, processing
- * advances to the next ECB.  processing advances to the next ECB.  If the
- * result is non-zero; For each ECB, it first determines the The ECB
- * abstraction allows disjoint consumers to multiplex on single probes.
+ * advances to the next ECB. The ECB abstraction allows disjoint consumers
+ * to multiplex on single probes.
+ *
+ * Execution of the ECB results in consuming dte_size bytes in the buffer
+ * to record data.  During execution, dte_needed bytes must be available in
+ * the buffer.  This space is used for both recorded data and tuple data.
  */
 struct dtrace_ecb {
        dtrace_epid_t dte_epid;                 /* enabled probe ID */
        uint32_t dte_alignment;                 /* required alignment */
-       size_t dte_needed;                      /* bytes needed */
-       size_t dte_size;                        /* total size of payload */
+       size_t dte_needed;                      /* space needed for execution */
+       size_t dte_size;                        /* size of recorded payload */
        dtrace_predicate_t *dte_predicate;      /* predicate, if any */
        dtrace_action_t *dte_action;            /* actions, if any */
        dtrace_ecb_t *dte_next;                 /* next ECB on probe */
@@ -268,27 +273,30 @@ typedef struct dtrace_aggregation {
  * the EPID, the consumer can determine the data layout.  (The data buffer
  * layout is shown schematically below.)  By assuring that one can determine
  * data layout from the EPID, the metadata stream can be separated from the
- * data stream -- simplifying the data stream enormously.
- *
- *      base of data buffer --->  +------+--------------------+------+
- *                                | EPID | data               | EPID |
- *                                +------+--------+------+----+------+
- *                                | data          | EPID | data      |
- *                                +---------------+------+-----------+
- *                                | data, cont.                      |
- *                                +------+--------------------+------+
- *                                | EPID | data               |      |
- *                                +------+--------------------+      |
- *                                |                ||                |
- *                                |                ||                |
- *                                |                \/                |
- *                                :                                  :
- *                                .                                  .
- *                                .                                  .
- *                                .                                  .
- *                                :                                  :
- *                                |                                  |
- *     limit of data buffer --->  +----------------------------------+
+ * data stream -- simplifying the data stream enormously.  The ECB always
+ * proceeds the recorded data as part of the dtrace_rechdr_t structure that
+ * includes the EPID and a high-resolution timestamp used for output ordering
+ * consistency.
+ *
+ *      base of data buffer --->  +--------+--------------------+--------+
+ *                                | rechdr | data               | rechdr |
+ *                                +--------+------+--------+----+--------+
+ *                                | data          | rechdr | data        |
+ *                                +---------------+--------+-------------+
+ *                                | data, cont.                          |
+ *                                +--------+--------------------+--------+
+ *                                | rechdr | data               |        |
+ *                                +--------+--------------------+        |
+ *                                |                ||                    |
+ *                                |                ||                    |
+ *                                |                \/                    |
+ *                                :                                      :
+ *                                .                                      .
+ *                                .                                      .
+ *                                .                                      .
+ *                                :                                      :
+ *                                |                                      |
+ *     limit of data buffer --->  +--------------------------------------+
  *
  * When evaluating an ECB, dtrace_probe() determines if the ECB's needs of the
  * principal buffer (both scratch and payload) exceed the available space.  If
@@ -426,6 +434,8 @@ typedef struct dtrace_buffer {
 #ifndef _LP64
        uint64_t dtb_pad1;
 #endif
+       uint64_t dtb_switched;                  /* time of last switch */
+       uint64_t dtb_interval;                  /* observed switch interval */
 } dtrace_buffer_t;
 
 /*