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TODO ------------------------------------------------------------------------
- ThreadScope DEADLOCKs occasionally, more often with --debuug, why?
- X Window System error sometimes?
- opening a non-existent file failure
- background of some widgets on Windows are white when they are grey in Linux
- when nothing is loaded, show a message to that effect in the window
- Make ^C work on Windows
- resizing the panes causes a grab lockup?
- jump to bookmark doesn't work in events window
- sort bookmark view by time?
- double-click a bookmark to jump to it?
- Delete key deletes bookmarks?
- hotkey to add a bookmark?
- fix, rewrite or disable partial redrawing of the graphs pane
that causes many of the graphical bugs reported in ThreadScope/TODO
- [GUI] (temporarily fixed on the offending display by increasing
timeline_labels_drawingarea width from 80 to 100)
I see "Spark poo size" as the left hand size label of the pool graphs,
with my Ubuntu gtk fonts; explanation: it's the wrapping
or rather the lack thereof; the wrapping is currently manual when
it should be automatic; what we should do is to calculate the width
based on the label size and let it do automatic wrapping
- 25%/50%/75% percentiles for pool size, see
figure 15
WARNING: unlike mean, the median and other percentiles can't be computed
from percentiles of subnodes of the trees --- they need the whole data
for the interval in question at each level of the tree. This increases
the cost from O(n) to O(n * log n), where n is the total number of samples.
Additional log n factor, in comparison with mean, is probably inevitable
unless we put the data in an array, because otherwise we have to
sort the data for each interval to find the k-th element.
An extra problem is that to get accurate percentiles for splices
that do not match a single subtree node, we have to get the whole
data for the splice again, completely repeating the calculations.
Then the preprocessing via creating the tree would only be useful
if the tree stores the whole data at each tree level, already partitioned
and the data for each slice may be gathered cheaply (but a bit inaccurately,
see the use of SparkStats.rescale in the current code) by only looking
at a few nodes of the tree at a single level, instead of traversing
a very long list. There are better data structures than the spark tree
for quick lookup of sorted data, so let's remove the pool sizes from
the spark tree altogether and hack them separately.
IDEA (dcoutts):,
basic idea is that we store something like a bitmap
(perhaps just 1D) at multiple resolutions
and resample from the nearest pre-computed bitmap;
which incidentally might be a good technique generally
might even take less memory than the current method
- resample the data (morally) uniformly, unless the sampling
is changed from GC time points to equal intervals
(note that with resampling, with enough extra inserted sample points,
the median approaches the mean, so calculating the median for pool size
does not make sense; however, percentiles still make sense --- they are
not just mean*(n/m), e.g., for y=5, all percentiles are 5,
while for y=x, from 0 to 10, they differ, regardless of sample density
and uniformity, except trivial cases)
- remove the grey halo in trivial cases of pool size,
like the line: ___/----, but keep min/max for ___/\___
- draw the scales (horizontal and vertical) in such a way that they're
always visible, regardless of scrolling
- review and document vertical scales and pool size graph code,
after they are rewritten
- [GUI] mark vertical scale units in the trace pane:
a long label might be "spark creation/conversion rate, unit spark/ms"
or "fizzled sparks/millisecond" or "Spark creation rate (sparks/millisecond)"
NOTE: DONE? this seems to have been done in the labels_drawingarea instead.
- [GUI] in the key, label the coloured areas, according to what they represent
the title of the plot is "spark creation rate" and the key will have things
for each colour; separate sections of the Key for
the activity vs sparks vs next-thing; make sure the user understands
that the _areas_ are proportional to the total number and graphs to rates
- [GUI] either fix tickboxes for HEC sets or make it two dimensional: one column
of tickboxes for activity, one column for spark creation, spark conversion
- the same aggregate style for the activity graph, to see min/max
(the green are does not convey any extra information, unlike
the tricolour areas in rate graphs)
- [GUI] put all the HEC0 bits together, both in the trace and in the timeline view
ie in the timeline, top -> bottom: activity HEC0, sparks HEC0,
activity HEC1, sparks HEC1, ...
- [GUI] in the trace window, enable/disable traces, but also
reorder them by just dragging and dropping
- test, in particular the quality of sampling, on the parfib suite;
ideally generate sampled events from accurate events and compare visually
and/or numerically
FIRST RELEASE ---------------------------------------------------------------
All of above
BUGS ------------------------------------------------------------------------
NOT QUITE DONE: - crash when zooming in too far (negative exponent)
- scrolling to the right, we get some over-rendering at the boundary
causing a thick line
- scrolling when event labels are on chops off some labels
- rendering bug when scrolling: we need to clip to the rectangle being
drawn, otherwise we overwrite other parts of the window when there
are long bars being drawn, which makes some events disappear.
- scrolling to the right at the end of the trace leaves an extra blue
line at the top.
- the vertical blue cursor line vanishes is some zoom levels
- sideways scrolling leaves curve rendering artifacts (e.g., the thicker
fragments of the flat line at the end of the Activity graph)
- sometimes 2 labels are written on top of each other even at max zoom,
e.g. "thread 3 yielding" and "thread 3 is runnable"
- sometimes 2 tick labels (showing time) overlap
- may be a feature: filling graphs with colours is from line 1 upwards,
not line 0, so lines at level 0 seem under the filled area, not level with it
- the light blue vertical lines get sometimes randomly darker when scrolling
by moving the scrollbar handle slowly to the right (probably caused
by testing an x coordinate up to integral division by slice or without
taking into account the hadj_value, so the line is drawn
many times when scrolling)
- a few levels of zoom in and then zoom out sometimes results in only
a right fragment of the timeline shown, no indication in the scrollbar
that scroll is possible, but scrolling indeed fixes the view
IDEAS ------------------------------------------------------------------------
- click and drag the view
- shift-click and drag to zoom to a region
- draw the detailed view in the background
- bookmarks
- add/remove
- save
- measure the time between two markers
- search for events in the event window
- render averaged areas properly
- indicate when one thread wakes up another thread, or a thread is migrated
- draw lines/arrows between the events?
- event list view
- respond to page up / page down / arrows (FOCUS)
- interact with bookmarks
- left pane for
- bookmarks
- list of traces
- traces would be a tree-view, e.g.
* HECs
* 0
* 1 etc.
* Threads
* 0
* 1 etc.
* live heap
* ETW / Linux Performance counters
* cache misses
* stalls
* etc.
- clicking on a trace adds that trace to the view, clicking again
removes it
- some way to reorder the traces?
- when rendering threads, we want some way to indicate the time
between creation and death - colour grey?
- a better progress bar
- [GUI] animate zoom level transitions:
ways to make the zoom in/out less confusing for users
(e.g. the sudden appearance of spikiness once thresholds)
animating the transitions would make it clearer
generate the bitmap of the higher resolution new view,
and animate it expanding to cover the new view
it'd be quick since it's just bitmap scaling
so the user can see the region in the old view
that is expanding out to become the new view
- [GUI] let the user set the interval size/scale,
as an advanced option, _separately_ for each graph stack,
each HEC, each visible region at the current zoom level,
each selected region (if they are implemented)
- [GUI] a button for vertical zoom (clip graphs if they don't fit at that zoom)
and/or select regions of time in the view
and zoom only that region of display;
- [GUI] an option to automatically change scale at zoom in to take
into account only the visible and smoothed part of the graphs
- [GUI] select a region and display it in a separate tab
(e.g. next to the events tab) and/or show in the tab for that selected time
period how many sparks of each kind in that time: summary statistics
for points in time, or periods of time; make the height of the graph
in the tab configurable/resizable with mouse, or just take the whole screen
- [GUI] scroll around the graph image via a small zoomed out window
"The Information Mural: A Technique for Displaying
and Navigating Large Information Spaces"
- [GUI] label coloured areas with a mouseover, according to what they represent
- catch exceptions in event handlers and emit a helpful error message of some
kind. tryEvent swallows exceptions, so it's not good enough.
- move the text entents stuff out of drawing ThreadRuns
- overlay ETW events
- integrate strace events in the event view on Linux
- colour threads differently
- thread names rather than numbers
- live heap graph
- summary analysis
- perhaps draw the graphs even if only the fully-accurate,
per-spark events are present in the logs (by transforming them
to the sampled format)
- and/or extrapolate data for large zoom levels with scarce samples
by slated lines, not just horizontal lines (which work great with
numerous enough samples, though)
- merge adjacent 0 samples:
if we have equal adjacent samples we just take the second/last
can be done when it's still a list, before making the tree;
simple linear pass, and lazy too;
does not make sense in per-spark events mode
- use the extra info about when the spark pool gets full and empty;
we know when the spark pool becomes empty because we can observe
that the threads evaluating sparks terminate; similarly, we know overflow
only occurs when the pool is full; but note the following:
"dcoutts: also noticed that we cannot currently reliably discover when the spark
queue is empty. I had thought that "the" spark thread terminating
implied that the queue is empty, however there can be multiple spark
threads and they can also terminate when there are other threads on that
capability's run queue (normal forkIO work takes precedence over
evaluating sparks)"
- consider making the graphs more accurate by drilling down the tree
to the base events at each slice borders:
they don't go down to the base events at each slice boundary
but only at the two viewport borders (hence the extra slices
at the ends dcoutts noticed).
The current state generally this results in smoothing the curve,
but a side-effect is that the graphs grow higher visually
(the max is higher) as the zoom level increases.
- or increase the accuracy by dividing increments not by the slice
length (implicitly), but the length of the sum of tree node spans
that cover the slice, similarly as in gnuplot graphs
- perhaps we should change the spark event sampling to emit events
every N sparks rather than at GC; but only if experiments (do more accurate
sampling and compare the general look of the graphs)
show that linear extrapolation of the GC data is not correct
(large spark transitions happen in the long periods between GC
and we don't know when exactly) (the 4K pool size guarantees that at least
with large visible absolute spark transition, the invisible transitions
can't be huge in proportion to the visible ones, so then linear extrapolation
is correct))
- integrate info about the time taken by sparks, via shades of green
(a shade per pixel of vertical line, indicating the average size
of sparks represented by the pixel/line (started/converted there))
or via scaling the creation/conversion graphs by the spark size
(instead of the area being the number of sparks,
it's proportional to the amount of work (ie eval time)
of the sparks in the interval)
- use adaptive interval, depending on the sample density at the viewed fragment
- perhaps, depending on sample density, alternate between raw data,
min/max, percentiles; so the raw data line slowly explodes into a band,
a big smudge, like a string of beads, that gets even more detailed
and perhaps wider, when data density/uniformity allows it;
in other words: a thin line means we only guess that's where the data might be
a thicker one, with mix/max means we have some data,
but too irregular/scarce to say more, and full thickness line,
with percentiles means we have enough data or evenly distributed enough
to say all
- have *configurable* colors, like in Eden
- dynamic strategy labelling (lots of stuff has to be done elsewhere, first)
- Eden TV has good visualisation for messages between processes & nodes,
(steal it, when we do more work on Cloud Haskell)
- user-generated events in eventlog: if implemented, visualize them
- show time corresponding to the eventlog buffer flushing,
after the event for this introduced
- verify correctness of the input eventlog, when event state transition machines
for events defined and implemented
- tidy up menu option
- overlaps should be gone now. fix ticks
- key is messed up (we shouldn't be using fixed coordinates here, font
sizes are variable)
- when there are no events, we crash in last
- fix event colours (key doesn't match)
- fix the ticks: labels overlap sometimes
- don't draw overlapping labels
- spark conversion and spark pool size graphs
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