Improve trace doc

doc/doxygen/chapters/starpu_performances/offline_performance_tools.doxy

@@ -232,8 +232,8 @@ starpu_task_insert()
 \li <b>Iteration</b>: refers to the iteration number of the computation, as set by starpu_iteration_push() at the beginning of submission loops and starpu_iteration_pop() at the end of submission loops
 \li <b>JobId</b>: represents a unique identifier for the specific task, as returned by starpu_task_get_job_id()
 \li <b>NumaNodes</b>: refers to the NUMA node where the data is stored, the environment variable \ref STARPU_FXT_EVENTS needs to contain \c TASK_VERBOSE_EXTRA, otherwise it will be -1
-\li <b>Params</b>: represents parameters or input/output types and sizes, possibly indicating the dimensions of the matrices
-\li <b>Size</b>: represents the size of the data being operated on in bytes
+\li <b>Params</b>: represents parameters or input/output types and sizes, possibly indicating the dimensions of the matrices, depending on how the function starpu_data_interface_ops::describe of the datatype is implemented
+\li <b>Size</b>: represents the size of the data being operated on in bytes, computed as the sum of the data sizes of each data handle manipulated by the task
 \li <b>Subiteration</b>: represents a sub-iteration number if the computation was part of a larger iteration or loop, as set by starpu_iteration_push()
 \li <b>SubmitOrder</b>: represents the order in which the task was submitted by
 the application
@@ -400,6 +400,23 @@ It is possible to get a graphical output of the graph by using the
 $ dot -Tpdf dag.dot -o output.pdf
 \endverbatim
 
+
+or visualize it directly with a program like <c>xdot</c>:
+
+\verbatim
+$ xdot dag.dot
+\endverbatim
+
+In the task graph, the color of each node is computed as follows:
+<ol>
+    <li>If the codelet defined a color (see \ref starpu_codelet::color), this color is used;</li>
+    <li>If the option <c>-c</c> of <c>starpu_fxt_tool</c> was set, all tasks having the same name will have the same color;</li>
+    <li>Otherwise, the color will represent on which worker the task was executed (green for CPUs and yellow to red for accelerators.</li>
+</ol>
+
+Moreover, the option <c>-no-acquire</c> of <c>starpu_fxt_tool</c> hides StarPU internal tasks for data acquisition from the graph. On the contrary, the option <c>-internal</c> shows more internal tasks.
+
+
 \subsection TraceTaskDetails Getting Task Details
 
 Another generated trace file gives details on the executed tasks. The

src/debug/traces/starpu_fxt.c

@@ -3052,41 +3052,44 @@ static void handle_task_name(struct fxt_ev_64 *ev, struct starpu_fxt_options *op
 	struct task_info *task = get_task(job_id, options->file_rank);
 	int worker = find_worker_id(prefixTOnodeid(prefix), ev->param[1]);
 
-	const char *color;
-	char buffer[32];
-	int code;
-	if (task->color != 0)
-	{
-		snprintf(buffer, sizeof(buffer), "#%06x", task->color);
-		color = &buffer[0];
-		code = ((task->color & 0xff) +
-			((task->color >> 8) & 0xff) +
-			((task->color >> 16) & 0xff)) / 256;
-	}
-	else if (options->per_task_colour)
-	{
-		unsigned red = get_color_symbol_red(name)/4;
-		unsigned green = get_color_symbol_green(name)/4;
-		unsigned blue = get_color_symbol_blue(name)/4;
-		snprintf(buffer, sizeof(buffer), "#%s%x%s%x%s%x",
-			 red < 16 ? "0" : "", red,
-			 green < 16 ? "0" : "", green,
-			 blue < 16 ? "0" : "", blue);
-		color = &buffer[0];
-		code = (red + green + blue) / 256;
-	}
-	else
-	{
-		color= (worker < 0)?"#aaaaaa":get_worker_color(worker);
-		code = 0;
-	}
-
 	if (!task->name)
 		task->name = strdup(name);
 
-	char *fontcolor = code <= 1 ? "white" : "black";
 	if (!task->exclude_from_dag && show_task(task, options))
+	{
+		const char *color;
+		char buffer[32];
+		int code;
+		if (task->color != 0)
+		{
+			snprintf(buffer, sizeof(buffer), "#%06x", task->color);
+			color = &buffer[0];
+			code = ((task->color & 0xff) +
+				((task->color >> 8) & 0xff) +
+				((task->color >> 16) & 0xff)) / 256;
+		}
+		else if (options->per_task_colour)
+		{
+			unsigned red = get_color_symbol_red(name)/4;
+			unsigned green = get_color_symbol_green(name)/4;
+			unsigned blue = get_color_symbol_blue(name)/4;
+			snprintf(buffer, sizeof(buffer), "#%s%x%s%x%s%x",
+				red < 16 ? "0" : "", red,
+				green < 16 ? "0" : "", green,
+				blue < 16 ? "0" : "", blue);
+			color = &buffer[0];
+			code = (red + green + blue) / 256;
+		}
+		else
+		{
+			color= (worker < 0)?"#aaaaaa":get_worker_color(worker);
+			code = 0;
+		}
+
+
+		char *fontcolor = code <= 1 ? "white" : "black";
 		_starpu_fxt_dag_set_task_name(options->file_prefix, job_id, task->name, color, fontcolor);
+	}
 }
 
 #ifdef STARPU_RECURSIVE_TASKS