Graph x-axis (order) can use floating-point labels for integer only data


Bugzilla Link	PR31581
Status	NEW
Importance	P normal
Reported by	James Greenhalgh (james.greenhalgh@arm.com)
Reported on	2017-01-09 07:47:05 -0800
Last modified on	2017-01-09 07:47:05 -0800
Version	unspecified
Hardware	PC Linux
CC	daniel@zuster.org
Fixed by commit(s)
Attachments	`order-axis-fp.png` (1735 bytes, image/png)
Blocks
Blocked by
See also

Created attachment 17820
Image showing a floating-point x-axis

In the GCC team at ARM we use LNT for performance tracking. We build a JSON
representation of our benchmark data, and then importing it to LNT for analysis
and visualization. We make regular builds, which are numbered sequentially, and
we use this number in the ["Run"]["Info"]["run_order"] field of the JSON we
import.

That gives us a run order which looks like: 1167, 1168, 1169, 1170, 1171, etc.
all integer numbers.

At particular unlucky zoom values the x-axis of the graph of a benchmark's
performance can pick label points for "Order" which are non-integer, for
example in the attached image over the range of runs I mentioned above it has
picked 1167.5.0, 1170.0, 1172.5, 1175.0, with data points spread out in that
range.

This looks odd, and is not a natural way to label the graph, but does not cause
any further issues. Zooming in/out, resizing the window, or adding additional
runs can all fix the issue, which (without knowing the code base) I'd guess was
just the graphing library used not knowing that run orders should generally be
treated as integer data.

Quuxplusone / LLVMBugzillaTest

Graph x-axis (order) can use floating-point labels for integer only data #30554