From 9e6f69132584c9ccd2842c9e01f8255e7ace8e94 Mon Sep 17 00:00:00 2001 From: Rodrigo Arias Date: Tue, 17 Sep 2024 13:30:21 +0200 Subject: [PATCH] Add examples in some trace concepts --- doc/user/concepts/trace-model.md | 63 +++++++++++++++++++++++++------- 1 file changed, 50 insertions(+), 13 deletions(-) diff --git a/doc/user/concepts/trace-model.md b/doc/user/concepts/trace-model.md index 318e42b..ff743aa 100644 --- a/doc/user/concepts/trace-model.md +++ b/doc/user/concepts/trace-model.md @@ -1,6 +1,7 @@ -# Trace model +# Trace concepts -An event model is composed by a group of runtime events +When using libovni to generate traces or the emulator to process them, there are +several concepts to keep in mind. ## Trace @@ -9,8 +10,8 @@ known as a trace. A runtime trace stores the information as-is in disk from a program execution. While a emulation trace is generated from the runtime trace for visualization with Paraver. -All the information is always stored inside the same directory, by default -`ovni/`, which is known as the trace directory. +Both runtime and emulation traces are always stored inside the same directory, +by default `ovni/`, which is known as the *trace directory*. ## Event @@ -18,6 +19,26 @@ An event is a point in time that has some information associated. Events written at runtime by libovni have at MCV, a clock and a optional payload. The list of all events recognized by the emulator can be found [here](../emulation/events.md). +Events can be displayed by ovnidump, which shows an explanation of what the +event means: + +```txt +$ ovnidump ovni/loom.hop.nosv-u1000/proc.1121064 | grep -A 10 VTx | head +517267929632815 VTx thread.1121064 executes the task 1 with bodyid 0 +517267930261672 VYc thread.1121064 creates task type 2 with label "task" +517267930875858 VTC thread.1121064 creates parallel task 2 with type 2 +517267930877789 VU[ thread.1121064 starts submitting a task +517267930877990 VU] thread.1121064 stops submitting a task +517267930878098 VTC thread.1121064 creates parallel task 3 with type 2 +517267930878196 VU[ thread.1121064 starts submitting a task +517267930878349 VU] thread.1121064 stops submitting a task +517267930878432 VTC thread.1121064 creates parallel task 4 with type 2 +517267930878494 VU[ thread.1121064 starts submitting a task +``` + +There are two types or events: normal and jumbo events, the latter can hold +large attached payloads. + ## State A state is a discrete value that can change over time based on the events the @@ -26,10 +47,24 @@ then written to the Paraver traces. An example is the thread state, which can change over time based on the events `OH*` that indicate a state transition of the current thread. +In contrast with an event, states have a duration associated which can usually +be observed in Paraver. + ## MCV -The MCV acronym is short of Model-Class-Value, which is a three character (byte) -identification for events. +The MCV acronym is the abbreviation of Model-Class-Value, which are a three +characters that identify any event. The MCV is shown in the ovnitop and ovnidump +tools and allows easy filtering with grep, for a single or related events: + +``` +$ ovnitop ovni | grep VT +VTe 20002 +VTx 20002 +VTC 200 +VTc 2 +VTp 1 +VTr 1 +``` ## Clock @@ -53,6 +88,14 @@ An event model is composed of several components: ## Payload Events may have associated additional information which is stored in the stream. +Normal events can hold up to 16 bytes, otherwise the jumbo events must be used +to hold additional payload. + +## Stream + +A stream is a directory which contains a binary stream and the associated stream +metadata file. Each stream is associated with a given part of a system. As of +now, libovni can only generate streams associated to [threads](part-model.md#thread). ## Binary stream @@ -63,10 +106,4 @@ Notice that each event may have different length. ## Stream metadata The stream metadata is a JSON file named `stream.json` which holds information -about the stream. - -## Stream - -A stream is a directory which contains a binary stream and the associated stream -metadata file. Each stream is associated with a given part of a system. As of -now, libovni can only generate streams associated to [threads](part-model.md#thread). +about the stream itself.