[1.0.0] - Nov 9, 2021
Self-profiler revamp
The self-profiler remains a useful tool for troubleshooting DDlog performance
issues. It runs with low overhead, allows enabling/disabling CPU and change
profiling at runtime to only instrument parts of the program, and because it is
integrated into the DDlog runtime it can precisely match each DD operator to the
corresponding DDlog operator. DDshow does not currently have these features.
In this release we revamp the self profiler to improve its ergonomics. The new
self-profiler has the following features:
-
Produces profiles in the form of interactive HTML tables. Each
row in the table represents a DD operator and contains operator
description, e.g., "Arrange relation 'Rel1' by 'x,y,z'" along with
links to one or more source code location that this operator
corresponds to (e.g., all locations where this specific arrangement
of 'Rel1' is used). -
The new
dump_profileAPI dumps the profile into an HTML file
on the disk instead of returning it as a string. All profiles
generated by the same process are generated in the same folder, even
if the process creates multiple instances of DDlog. This folder
also contains a complete snapshot of all DDlog code in the
program, so that the profiler can show program sources even when
the program does not run on the same system where it was compiled. -
Internally, the self-profiler represents profiles using a
well-defined JSON format. New APIs were added to extract
each of the four profiles currently supported by DDlog (arrangement
size profile, peak arrangement size profile, change profile, and
CPU profile) in the JSON format, for automatic processing by
third-party tools.