- Solves all the weaknesses idenfied in the actual boundaryless traceset
reading.
+
+
+
+
+- Revised Events Requests Servicing Algorithm (v2)
+
+typedef LttvEventsRequestPrio guint;
+
+typedef struct _EventsRequest {
+ gpointer viewer_data;
+ gboolean servicing; /* service in progress: TRUE */
+ LttvEventsRequestPrio prio; /* Ev. Req. priority */
+ LttTime start_time; /* Unset : { 0, 0 } */
+ LttvTracesetContextPosition *start_position; /* Unset : num_traces = 0 */
+ gboolean stop_flag; /* Continue:TRUE Stop:FALSE */
+ LttTime end_time; /* Unset : { 0, 0 } */
+ guint num_events; /* Unset : G_MAXUINT */
+ LttvTracesetContextPosition *end_position; /* Unset : num_traces = 0 */
+ LttvHooks *before_traceset; /* Unset : NULL */
+ LttvHooks *before_trace; /* Unset : NULL */
+ LttvHooks *before_tracefile;/* Unset : NULL */
+ LttvHooks *event; /* Unset : NULL */
+ LttvHooksById *event_by_id; /* Unset : NULL */
+ LttvHooks *after_tracefile; /* Unset : NULL */
+ LttvHooks *after_trace; /* Unset : NULL */
+ LttvHooks *after_traceset; /* Unset : NULL */
+ LttvHooks *before_chunk; /* Unset : NULL */
+ LttvHooks *after_chunk /* Unset : NULL */
+} EventsRequest;
+
+
+The reads are splitted in chunks. After a chunk is over, we want to check if
+there is a GTK Event pending and execute it. It can add or remove events
+requests from the event requests list. If it happens, we want to start over
+the algorithm from the beginning.
+
+Two levels of priority exists. High priority and low priority. High prio
+requests are serviced first, even if lower priority requests has lower start
+time or position.
+
+
+Data structures necessary :
+
+List of requests added to context : list_in
+List of requests not added to context : list_out
+
+Initial state :
+
+list_in : empty
+list_out : many events requests
+
+
+A. While list_in !empty and list_out !empty and !GTK Event pending
+ 1. If list_in is empty (need a seek)
+ 1.1 Add requests to list_in
+ 1.1.1 Find all time requests with the highest priority and lowest start
+ time in list_out (ltime)
+ 1.1.2 Find all position requests with the highest priority and lowest
+ position in list_out (lpos)
+ 1.1.3 If lpos.prio > ltime.prio
+ || (lpos.prio == ltime.prio && lpos.start time < ltime)
+ - Add lpos to list_in, remove them from list_out
+ 1.1.4 Else, (lpos.prio < ltime.prio
+ ||(lpos.prio == ltime.prio && lpos.start time >= ltime))
+ - Add ltime to list_in, remove them from list_out
+ 1.2 Seek
+ 1.2.1 If first request in list_in is a time request
+ 1.2.1.1 Seek to that time
+ 1.2.2 Else, the first request in list_in is a position request
+ 1.2.2.1 If the position is the same than the saved state, restore state
+ 1.2.2.1 Else, seek to that position
+ 1.3 Add hooks and call begin for all list_in members
+ 1.3.1 If !servicing
+ - begin hooks called
+ - servicing = TRUE
+ 1.3.2 call before_chunk
+ 1.3.3 events hooks added
+ 2. Else, list_in is not empty, we continue a read
+ 2.1 For each req of list_out
+ - if req.start time == current context time
+ - Add to list_in, remove from list_out
+ - If !servicing
+ - Call begin
+ - servicing = TRUE
+ - Call before_chunk
+ - events hooks added
+ - if req.start position == current position
+ - Add to list_in, remove from list_out
+ - If !servicing
+ - Call begin
+ - servicing = TRUE
+ - Call before_chunk
+ - events hooks added
+
+ 3. Find end criterions
+ 3.1 End time
+ 3.1.1 Find lowest end time in list_in
+ 3.1.2 Find lowest start time in list_out (>= than current time*)
+ * To eliminate lower prio requests
+ 3.1.3 Use lowest of both as end time
+ 3.2 Number of events
+ 3.2.1 Find lowest number of events in list_in
+ 3.2.2 Use min(CHUNK_NUM_EVENTS, min num events in list_in) as num_events
+ 3.3 End position
+ 3.3.1 Find lowest end position in list_in
+ 3.3.2 Find lowest start position in list_out (>= than current
+ position)
+ 3.3.3 Use lowest of both as end position
+
+ 4. Call process traceset middle
+ 4.1 Call process traceset middle (Use end criterion found in 3)
+ * note : end criterion can also be viewer's hook returning TRUE
+ 5. After process traceset middle
+ - if current context time > traceset.end time
+ - For each req in list_in
+ - Call end for req
+ - Remove events hooks for req
+ - remove req from list_in
+ 5.1 For each req in list_in
+ - req.num -= count
+ - if req.num == 0
+ - Call end for req
+ - Remove events hooks for req
+ - remove req from list_in
+ - if current context time > req.end time
+ - Call end for req
+ - Remove events hooks for req
+ - remove req from list_in
+ - if req.end pos == current pos
+ - Call end for req
+ - Remove events hooks for req
+ - remove req from list_in
+ - if req.stop_flag == TRUE
+ - Call end for req
+ - Remove events hooks for req
+ - remove req from list_in
+ - if exists one events requests in list_out that has
+ higher priority and time != current time
+ - Use current position as start position for req
+ - Remove start time from req
+ - Call after_chunk for req
+ - Remove event hooks for req
+ - Put req back in list_out, remove from list_in
+ - Save current state into saved_state.
+
+B. When interrupted
+ 1. for each request in list_in
+ 1.1. Use current postition as start position
+ 1.2. Remove start time
+ 1.3. Call after_chunk
+ 1.4. Remove event hooks
+ 1.5. Put it back in list_out
+ 2. Save current state into saved_state.
+ 2.1 Free old saved state.
+ 2.2 save current state.
+
+
+
+
+
+Notes :
+End criterions for process traceset middle :
+If the criterion is reached, event is out of boundaries and we return.
+Current time >= End time
+Event count > Number of events
+Current position >= End position
+Last hook list called returned TRUE
+
+The >= for position is necessary to make ensure consistency between start time
+requests and positions requests that happens to be at the exact same start time
+and position.
+
+We only keep one saved state in memory. If, for example, a low priority
+servicing is interrupted, a high priority is serviced, then the low priority
+will use the saved state to start back where it was instead of seeking to the
+time. In the very specific case where a low priority servicing is interrupted,
+and then a high priority servicing on top of it is also interrupted, well, the
+low priority will loose its state and will have to seek back. It should not
+occur often. The solution to it would be to save one state per priority.
+
+
projects / lttv.git / commitdiff
