format.html: update lttng trace format

git-svn-id: http://ltt.polymtl.ca/svn@2935 04897980-b3bd-0310-b5e0-8ef037075253

diff --git a/ltt/branches/poly/doc/developer/format.html b/ltt/branches/poly/doc/developer/format.html
index 254700af8f61cc5bf013073da06dc5a356dc9b19..e19b5d19c06ac3db8e353abfe11595b3a17055e9 100644 (file)
--- a/ltt/branches/poly/doc/developer/format.html
+++ b/ltt/branches/poly/doc/developer/format.html
@@ -8,34 +8,22 @@
 <h1>The LTTng trace format</h1>
 
 <P>
-This document describes the LTTng trace format. It should be used only by
+<EM>Last update: 2008/05/23</EM>
+
+<P>
+This document describes the LTTng trace format. It should be useful mainly to
 developers who code the LTTng tracer or the traceread LTTV library, as this
 library offers all the necessary abstractions on top of the raw trace data.
 
 <P>
-A trace is contained in a directory tree. To send a trace remotely,
-the directory tree may be tar-gzipped. Trace foo, placed in the home
-directory of user john, /home/john, would have the following content:
+A trace is contained in a directory tree. To send a trace remotely, the
+directory tree may be tar-gzipped. The trace <tt>foo</tt>, placed in the home
+directory of user john, /home/john, would have the following contents:
 
 <PRE><TT>
 $ cd /home/john
 $ tree foo
 foo/
-|-- eventdefs
-|   |-- core.xml
-|   |-- fs.xml
-|   |-- ipc.xml
-|   |-- kernel.xml
-|   |-- memory.xml
-|   |-- network.xml
-|   |-- process.xml
-|   |-- s390_kernel.xml
-|   |-- socket.xml
-|   |-- timer.xml
-|   `-- ...
-|-- info
-|   |-- bookmarks.xml
-|   `-- system.xml
 |-- control
 |   |-- facilities_0
 |   |-- facilities_1
@@ -55,50 +43,23 @@ foo/
 
 </TT></PRE>
 
-<P>
-The eventdefs directory contains the events descriptions for all the
-facilities used. The syntax is a simple subset of XML; XML is widely
-known and easily parsed or hand edited. Each file contains one or more
-<FACILITY NAME=name>...</FACILITY> elements. Indeed, several
-facilities may have the same name but different content (and thus will
-generate a different checksum). It typically happens when, while tracing
-is enabled, a module using the named facility is unloaded, modified
-(along with the description of some events), recompiled and reloaded.
-Then, the trace will contain events from two different, similarly named,
-facility versions.
-
-<P>
-A small number of events are predefined, part of the "core" facility, 
-and are not present there. These "core" events include "facility_load", 
-"facility_unload", "time_heartbeat" and "state_dump_facility_load".
-
 <P>
 The root directory contains a tracefile for each cpu, numbered from 0, 
 in .trace format. A uniprocessor thus only contains the file cpu_0. 
 A multi-processor with some unused (possibly hotplug) CPU slots may have some
-unused CPU numbers. For instance a 8 way SMP board with 6 CPUs randomly 
+unused CPU numbers. For instance an 8 way SMP board with 6 CPUs randomly 
 installed may produce tracefiles named 0, 1, 2, 4, 6, 7.
 
 <P>
-The files in the control directory also follow the .trace format and are also
-per cpu. 
-The "facilities" file only contains "core" facility_load, facility_unload,
-time_heartbeat and state_dump_facility_load events
-and is used to determine the facilities used and the code range assigned 
-to each facility. The other control files contain the initial system
-state and various subsequent important events, for example process 
-creations and exit. The interest of placing such subsequent events 
-in control trace files instead of (or in addition to) in the per cpu 
-trace files is that they may be accessed more quickly/conveniently 
-and that they may be kept even when the per cpu files are overwritten 
-in "flight recorder mode".
-
-<P>
-The info directory contains in system.xml a description of the system on which
-the trace was created as well as different user annotations in bookmark.xml.
-This directory may also contain various information about the trace, generated 
-during trace analysis (statistics, index...).
-
+The files in the control directory also follow the .trace format and are
+also per cpu.  The "facilities" files only contain "core" marker_id,
+marker_format and time_heartbeat events. The first two are used to describe the
+events that are in the trace. The other control files contain the initial
+system state and various subsequent important events, for example process
+creations and exit. The interest of placing such subsequent events in control
+trace files instead of (or in addition to) in the per cpu trace files is that
+they may be accessed more quickly/conveniently and that they may be kept even
+when the per cpu files are overwritten in "flight recorder mode".
 
 <H2>Trace format</H2>
 
@@ -119,8 +80,7 @@ event 2 variable length data
 padding
 </TT></PRE>
 
-<P>
-The block start/end header
+<H3>The block start/end header</H3>
 
 <PRE><TT>
 begin
@@ -132,7 +92,7 @@ begin
 end
        * the end of buffer information
        uint64 cycle_count
-               * TSC at the beginning of the buffer
+               * TSC at the end of the buffer
        uint64 freq
                * frequency of the CPUs at the end of the buffer.
 uint32 lost_size
@@ -143,8 +103,7 @@ uint32 buf_size
 
 
 
-<P>
-The trace header
+<H3>The trace header</H3>
 
 <PRE><TT>
 uint32 magic_number
@@ -169,10 +128,13 @@ uint8     has_heartbeat
        * Does this trace have heartbeat timer event activated ?
                Yes (1) -> Event header has 32 bits TSC
                No (0) -> Event header has 64 bits TSC
-uint8 has_alignment
-       * Is the information in this trace aligned ?
-               Yes (1) -> aligned on min(arch size, atomic data size).
+uint8 alignment
+       * Are event headers in this trace aligned ?
+               Yes -> the value indicates the alignment
                No (0) -> data is packed.
+uint8 tsc_lsb_truncate
+uint8 tscbits
+uint8 compact_data_shift
 uint32 freq_scale
                event time is always calculated from :
                        trace_start_time + ((event_tsc - trace_start_tsc) * (freq / freq_scale))
@@ -193,12 +155,11 @@ start_time
 </TT></PRE>
 
 
-<P>
-Event header
+<H3>Event header</H3>
 
 <P>
-Event headers differs depending on those conditions : does the traced system has
-a heartbeat timer ? Is tracing alignment activated ?
+Event headers differ according to the following conditions : does the
+traced system have a heartbeat timer? Is tracing alignment activated?
 
 <P>
 Event header :
@@ -222,13 +183,12 @@ uint16 event_size
 Event header alignment
 
 <P>
-If trace alignment is activated (has_alignment), the event header is aligned
-on the architecture size (void pointer size). In addition, a padding is
-automatically added after the event header so the variable length data is
-automatically aligned on the architecture size.
+If trace alignment is activated (<tt>alignment</tt>), the event header is
+aligned. In addition, padding is automatically added after the event header so
+the variable length data is automatically aligned on the architecture size.
 
 <P>
-
+<!--
 <H2>System description</H2>
 
 <P>
@@ -260,7 +220,7 @@ Some comments about the system
 The system attributes kernel_name, node_name, kernel_release,
  kernel_version, machine, processor, hardware_platform and operating_system
 come from the uname(1) program. The domainname attribute is obtained from
-the "hostname --domain" command. The arch_size attribute is one of
+the "hostname &#045;&#045;domain" command. The arch_size attribute is one of
 LP32, ILP32, LP64 or ILP64 and specifies the length in bits of integers (I),
 long (L) and pointers (P). The endian attribute is "little" or "big".
 While the arch_size and endian attributes could be deduced from the platform
@@ -273,213 +233,6 @@ directory.
 Within the system element, the text enclosed may describe further the
 system traced.
 
-
-<H2>Event type descriptions</H2>
-
-<P>
-A facility contains the descriptions of several event types. When a structure
-is reused in several event types, a named type is defined and may be referenced
-by several other event types or named types.
-
-<PRE><TT>
-&lt;facility name=facility_name&gt;
-  &lt;description&gt;Some text&lt;/description&gt;
-  &lt;event name=eventtype_name&gt;
-    &lt;description&gt;Some text&lt;/description&gt;
-    --type structure--
-  &lt;/event&gt;
-  ...
-  &lt;type name=type_name&gt;
-    --type structure--
-  &lt;/type&gt;
-&lt;/facility&gt;
-</TT></PRE>
-
-<P>
-The type structure may be one of the following primitive type elements.
-Whenever the keyword isize is used, the allowed values are 
-short, medium, long, 1, 2, 4, 8, indicating the size in bytes.
-The fsize keyword represents one of medium, long, 4 and 8 bytes.
-
-<PRE><TT>
-&lt;int size=isize format="printf format"/&gt;
-
-&lt;uint size=isize format="printf format"/&gt;
-
-&lt;float size=fsize format="printf format"/&gt;
-
-&lt;string format="printf format"/&gt;
-
-&lt;enum size=isize format="printf format"&gt;label1 label2 ...&lt;/enum&gt;
-</TT></PRE>
-
-<P>
-The string is null terminated. For the enumeration, the size of the integer
-used for its representation is specified.
-
-<P>
-The type structure may also be a compound type.
-
-<PRE><TT>
-&lt;array size=n&gt; --type structure-- &lt;/array&gt;
-
-&lt;sequence lengthsize=isize&gt; --type structure-- &lt;/sequence&gt;
-
-&lt;struct&gt;
-  &lt;field name=field_name&gt;
-    &lt;description&gt;Some text&lt;/description&gt;
-    --type structure--
-  &lt;/field&gt;
-  ...
-&lt;/struct&gt;
-
-&lt;union typecodesize=isize&gt;
-  &lt;field name=field_name&gt;
-    &lt;description&gt;Some text&lt;/description&gt;
-    --type structure--
-  &lt;/field&gt;
-  ...
-&lt;/union&gt;
-</TT></PRE>
-
-<P>
-Array is a fixed size array of length size. Sequence is a variable size
-array with its length stored as a prepended uint of length lengthsize. 
-A structure is simply an aggregation of fields. An union is one of its n 
-fields (variant record), as indicated by a preceeding code (0 to n - 1)
-of the specified size typecodesize.
-
-<P>
-Finally the type structure may be defined by referencing a named type.
-
-<PRE><TT>
-&lt;typeref name=type_name/&gt;
-</PRE></TT>
-
-<H2>Core events</H2>
-
-<P>
-The facility named "core" is always present and contains at least the
-following event types.
-
-<PRE><TT>
-&lt;event name=facility_load&gt;
-  &lt;description&gt;Facility used in the trace&lt;/description&gt;
-  &lt;struct&gt;
-    &lt;field name="name"&gt;&lt;string/&gt;&lt;/field&gt;
-    &lt;field name="checksum"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="id"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="int_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="long_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="pointer_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="size_t_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="has_alignment"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-  &lt;/struct&gt;
-&lt;/event&gt;
-
-&lt;event name=state_dump_facility_load&gt;
-  &lt;description&gt;Facility used in the trace&lt;/description&gt;
-  &lt;struct&gt;
-    &lt;field name="name"&gt;&lt;string/&gt;&lt;/field&gt;
-    &lt;field name="checksum"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="id"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="int_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="long_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="pointer_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="size_t_size"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="has_alignment"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-  &lt;/struct&gt;
-&lt;/event&gt;
-
-&lt;event name=time_heartbeat&gt;
-  &lt;description&gt;System time values sent periodically to minimize cycle counter 
-    drift with respect to real time clock and to detect cycle counter
-    rollovers
-  &lt;/description&gt;
-  &lt;typeref name=timestamp/&gt;
-&lt;/event&gt;
-
-&lt;type name=timestamp&gt;
-  &lt;struct&gt;
-    &lt;field name="seconds"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="nanoseconds"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="cycle_count"&gt;&lt;uint size=8/&gt;&lt;/field&gt;
-  &lt;/struct&gt;
-&lt;/event&gt;
-
-</TT></PRE>
-
-<H2>Control files</H2>
-
-<P>
-The interrupts file reflects the content of the /proc/interrupts system file.
-It contains one event describing each interrupt. At trace start, events are
-generated describing all the current interrupts. If the assignment of
-interrupts changes later, due to devices or device drivers being activated or
-deactivated, additional events may be added to the file. Each interrupt
-event has the following structure.
-
-<PRE><TT>
-&lt;event name=interrupt&gt;
-  &lt;description&gt;Interrupt request number assignment&lt;description&gt;
-  &lt;struct&gt;
-    &lt;field name="number"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="count"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="controller"&gt;&lt;string/&gt;&lt;/field&gt;
-    &lt;field name="name"&gt;&lt;string/&gt;&lt;/field&gt;
-  &lt;/struct&gt;
-&lt;/event&gt;
-</TT></PRE>
-
-<P>
-The processes file contains the list of processes already created when the
-trace starts. Each process describing event is modeled after the 
-/proc/self/status system file. The number of fields in this event is
-expected to be expanded in the future to include groups, signal masks,
-opened file descriptors and address maps.
-
-<PRE><TT>
-&lt;event name=process&gt;
-  &lt;description&gt;Existing process&lt;description&gt;
-  &lt;struct&gt;
-    &lt;field name="name"&gt;&lt;string/&gt;&lt;/field&gt;
-    &lt;field name="pid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="ppid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="tracer_pid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="uid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="euid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="suid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="fsuid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="gid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="egid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="sgid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="fsgid"&gt;&lt;uint size=4/&gt;&lt;/field&gt;
-    &lt;field name="state"&gt;&lt;enum size=4&gt;
-        Running WaitInterruptible WaitUninterruptible Zombie Traced Paging
-    &lt;/enum&gt;&lt;/field&gt;
-  &lt;/struct&gt;
-&lt;/event&gt;
-</TT></PRE>
-
-<H2>Facilities</H2>
-
-<P>
-Facilities define a granularity of events grouping for filtering, activation
-and compilation. Each facility does cost a table entry in the kernel (name,
-checksum, event type code range), or somewhere between 20 and 30 bytes. Having
-one facility per tracing statement in the kernel would be too much (assuming
-that they eventually are routinely inserted in the kernel code and replace 
-the 80000+ printk statements in some proportion). However, having a few 
-facilities, up to a few tens, would make sense.
-
-<P>
-The "builtin" facility contains a small number of predefined events which must
-always exist. The "core" facility contains a small subset of OS events which
-are almost always of interest (scheduling, interrupts, faults, system calls).
-Then, specialized facilities may exist for each subsystem (network, disks,
-USB, SCSI...).
- 
-
 <H2>Bookmarks</H2>
 
 <P>
@@ -498,10 +251,6 @@ The interval is defined using either "time=" or "start_time=" and
 "end_time=", or "cycle=" or "start_cycle=" and "end_cycle=". 
 The time is in seconds with decimals up to nanoseconds and cycle counts 
 are unsigned integers with a 64 bits range. The cpu attribute is optional.
-
+-->
 </BODY>
 </HTML>
-
-
-
-