diff options
Diffstat (limited to 'usr/src/uts/common/sys/dtrace_impl.h')
| -rw-r--r-- | usr/src/uts/common/sys/dtrace_impl.h | 59 |
1 files changed, 33 insertions, 26 deletions
diff --git a/usr/src/uts/common/sys/dtrace_impl.h b/usr/src/uts/common/sys/dtrace_impl.h index 3bebd0cb30..d780082137 100644 --- a/usr/src/uts/common/sys/dtrace_impl.h +++ b/usr/src/uts/common/sys/dtrace_impl.h @@ -26,6 +26,7 @@ /* * Copyright (c) 2011, Joyent, Inc. All rights reserved. + * Copyright (c) 2012 by Delphix. All rights reserved. */ #ifndef _SYS_DTRACE_IMPL_H @@ -199,15 +200,18 @@ 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 */ @@ -265,27 +269,30 @@ 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 |