Serial Debugging for Parallel Programs

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional debugging tools fail to provide a deterministic debugging experience for programs that execute in a distributed and non-serial fashion, leading to inaccuracies and a complex user experience due to out-of-order execution and parallel processing.

Innovation Solution

The system facilitates a serial debugging experience by using a distributed task scheduler to coordinate task execution, creating a logical call stack and allowing breakpoints to be hit sequentially, and providing deterministic stepping and breakpoint management, focusing on a single logical thread for user simplicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional debuggers attach simultaneously to individual processes for parallel programs, then the debugging tool can handle distributed execution, but the debugging experience becomes non-deterministic and inaccurate due to out-of-order execution

Engineering Contradiction:

Improveability to handle distributed executionVSAvoiddeterministic debugging experience

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the parallel execution into discrete tasks with defined execution orders. Each task is assigned a unique identifier and execution sequence, allowing the debugger to track and present tasks in a deterministic order despite their parallel execution. This segmentation enables the debugger to maintain a consistent view of program state across distributed processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary actions by establishing task execution orders and dependencies before actual execution occurs. The system pre-defines the sequence in which tasks should be presented to the user during debugging, ensuring that even though tasks execute in parallel, they are processed and displayed in a predetermined deterministic sequence.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If libraries allow program loops to execute out of order in parallel, then processing efficiency improves, but breakpoint collection becomes inaccurate and random

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidbreakpoint collection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback mechanisms where the debugger receives execution status information from parallel tasks and adjusts its breakpoint collection process accordingly. When tasks complete execution, the debugger receives feedback about their completion state and uses this information to accurately determine when breakpoints should be collected, ensuring precision despite out-of-order execution.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces dynamic breakpoint collection where the debugger adapts its breakpoint collection timing based on actual task execution progress. Rather than collecting breakpoints at fixed intervals or in predetermined order, the system dynamically adjusts collection timing based on task completion events, maintaining accuracy while allowing parallel execution flexibility.

Inventive Principle:

Principle #15Dynamics

3Loss of information

If traditional debuggers present all threads to the user during debugging, then complete thread visibility is achieved, but user complexity increases significantly

Engineering Contradiction:

Improvethread visibility completenessVSAvoiduser experience simplicity

Core Design Contradiction:

Loss of informationVSEase of operation

Solution Approach 1:

The patent merges multiple parallel threads into a unified task representation that preserves the logical structure of the program. By combining threads while maintaining their individual identities through task identifiers and execution orders, the system provides complete thread visibility while presenting a simplified, unified view to the user that is easier to navigate and understand.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent adds a new dimension to thread presentation by introducing task execution order and logical grouping as additional organizing principles. Instead of presenting threads only in their physical execution order, the system adds layers of organization based on task dependencies and execution sequence, creating a multi-dimensional view that reduces cognitive load while maintaining completeness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8843900B2Serial debugging experience for parallel programs

Publication Date: 2014.09.23 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

Systems, methods, and computer program products for facilitating a serial debugging experience for programs running in a distributed, non-deterministic, out-of-order (i.e., parallel) fashion are disclosed. Such systems, methods, and computer program products provide a modified combination of breakpoints, stepping, and call stacks that facilitate the ability to improve the debugging experience for out-of-order program execution. In an embodiment, a task scheduler provides a distributed task graph. Then, the user may hit breakpoints sequentially within the graph's execution and use deterministic stepping (i.e., step-in, step-out, and step-over functions) to create a logical call stack from a distributed task graph. Such embodiments allow the program to execute in a distributed and parallel manner, while presenting the user a sequential execution experience in the debugger.