Added to the lttvwindow API :
-- lttvwindow_events_request
-( MainWindow *main_win,
- LttTime start_time,
- LttvTracesetContextPosition start_position,
- LttTime end_time,
- guint num_events,
- LttvTracesetContextPosition end_position,
- LttvHooksById before_traceset,
- LttvHooksById before_trace,
- LttvHooksById before_tracefile,
- LttvHooksById middle,
- LttvHooksById after_tracefile,
- LttvHooksById after_trace,
- LttvHooksById after_traceset)
+void lttvwindow_events_request
+( Tab *tab,
+ const EventsRequest *events_request);
+
+void lttvwindow_events_request_remove_all
+( Tab *tab,
+ gconstpointer viewer);
Internal functions :
- lttvwindow_process_pending_requests
+Events Requests Removal
+
+A new API function will be necessary to let viewers remove all event requests
+they have made previously. By allowing this, no more out of bound requests will
+be serviced : a viewer that sees its time interval changed before the first
+servicing is completed can clear its previous events requests and make a new
+one for the new interval needed, considering the finished chunks as completed
+area.
+
+It is also very useful for dealing with the viewer destruction case : the viewer
+just has to remove its events requests from the main window before it gets
+destroyed.
+
+
+Permitted GTK Events Between Chunks
+
+All GTK Events will be enabled between chunks. This is due to the fact that the
+background processing and a high priority request are seen as the same case.
+While a background processing is in progress, the whole graphical interface must
+be enabled.
+
+We needed to deal with the coherence of background processing and diverse GTK
+events anyway. This algorithm provides a generalized way to deal with any type
+of request and any GTK events.
+
+
+Background Computation Request
+
+The types of background computation that can be requested by a viewer : state
+computation (main window scope) or viewer specific background computation.
+
+A background computation request is asked via lttvwindow_events_request, with a
+priority field set with a low priority.
+
+In the case of a background computation with viewer pointer field set to NULL,
+if a lttvwindow_events_request_remove_all is done on the viewer pointer, it will
+not affect the state computation as no viewer pointer will have been passed in
+the initial request. This is the expected result. For the background processings
+that call viewer's hooks, they will be removed.
+
+
+A New "Redraw" Button
+
+It will be used to redraw the viewers entirely. It is useful to restart the
+servicing after a "stop" action.
+
+A New "Continue" Button
+
+It will tell the viewers to send requests for damaged areas. It is useful to
+complete the servicing after a "stop" action.
+
+
+
+Tab change
+
+If a tab change occurs, we still want to do background processing.
+Events requests must be stocked in a list located in the same scope than the
+traceset context. Right now, this is tab scope. All functions called from the
+request servicing function must _not_ use the current_tab concept, as it may
+change. The idle function must the take a tab, and not the main window, as
+parameter.
+
+If a tab is removed, its associated idle events requests servicing function must
+also be removed.
+
+It now looks a lot more useful to give a Tab* to the viewer instead of a
+MainWindow*, as all the information needed by the viewer is located at the tab
+level. It will diminish the dependance upon the current tab concept.
+
+
+
+Idle function (lttvwindow_process_pending_requests)
+
+The idle function must return FALSE to be removed from the idle functions when
+no more events requests are pending. Otherwise, it returns TRUE. It will service
+requests until there is no more request left.
+
+
+
Implementation
- lttvwindow_events_request
-It adds the EventsRequest struct to the array of time requests pending and
-registers a pending request for the next g_idle if none is registered.
+It adds the an EventsRequest struct to the array of time requests
+pending and registers a pending request for the next g_idle if none is
+registered. The viewer can access this structure during the read as its
+hook_data. Only the stop_flag can be changed by the viewer through the
+event hooks.
+
+typedef LttvEventsRequestPrio guint;
typedef struct _EventsRequest {
- LttTime start_time, /* Unset : { 0, 0 } */
- LttvTracesetContextPosition start_position, /* Unset : num_traces = 0 */
- LttTime end_time, /* Unset : { 0, 0 } */
- guint num_events, /* Unset : G_MAXUINT */
- LttvTracesetContextPosition end_position, /* Unset : num_traces = 0 */
- LttvHooksById *before_traceset, /* Unset : NULL */
- LttvHooksById *before_trace, /* Unset : NULL */
- LttvHooksById *before_tracefile, /* Unset : NULL */
- LttvHooksById *middle, /* Unset : NULL */
- LttvHooksById *after_tracefile, /* Unset : NULL */
- LttvHooksById *after_trace, /* Unset : NULL */
- LttvHooksById *after_traceset /* Unset : NULL */
+ 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;
+
+- lttvwindow_events_request_remove_all
+
+It removes all the events requests from the pool that has their "viewer" field
+maching the viewer pointer given in argument.
+
+It calls the traceset/trace/tracefile end hooks for each request removed.
+
+
- lttvwindow_process_pending_requests
This internal function gets called by g_idle, taking care of the pending
calls. Here is the detailed description of the way it works :
-- Events Requests Servicing Algorithm
+
+- Revised Events Requests Servicing Algorithm (v2)
+
+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_out : many events requests
-While list_in !empty and list_out !empty
+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 lowest start time in list_out
- (ltime)
- 1.1.2 Find all position requests with the lowest position in list_out
- (lpos)
- 1.1.3 If lpos.start time < ltime
+ 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.start time >= ltime)
+ 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
+ - If first req in list_in start time != current time
+ - Seek to that time
1.2.2 Else, the first request in list_in is a position request
- 1.2.2.1 Seek to that position
- 1.3 Call begin for all list_in members
- (1.3.1 begin hooks called)
- (1.3.2 middle hooks added)
+ - If first req in list_in pos != current pos
+ - If the position is the same than the saved state, restore state
+ - 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
- - Call begin
+ - 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
- - Call begin
+ - 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
+ 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
+ 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
+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.
+
+
+
+
Weaknesses
-- None (nearly?) :)
+- There is a possibility that we must use seek if more than one interruption
+ occurs, i.e. low priority interrupted by addition of high priority, and then
+ high priority interrupted. The seek will be necessary for the low priority.
+ It could be a good idea to keep one saved_state per priority ?
Strengths
- Solves all the weaknesses idenfied in the actual boundaryless traceset
reading.
+
+- Background processing available.
+
projects / lttv.git / blobdiff