org_roam/Uni/20250331201944-ise_week_5.org

ISE Week 5

• Model free Tuning (for ORM) (pages 9-17)
• Model free Tuning (BestConfig) (pages 18-23)
• 5.1 Model-Free Tuning for ORM Systems - Intelligent Software Engineering
  • 1. Introduction and Background
  • 2. Architecture and Setup
  • 3. Stopping Criteria
    • a. Setting 1: t-test-based Stopping
    • b. Setting 2: Mutual Dominance Rate (MDR)
  • 4. Termination Condition
  • 5. Experimental Results
• 5.2 Model-Free Tuning with BestConfig - Intelligent Software Engineering
  • 1. Introduction and Background
  • 2. Architecture Overview
  • 3. DDS: Divide & Diverge Sampling
  • 4. RBS: Recursive Bound & Search
  • 5. Results and Observations

TODO Model free Tuning (for ORM) (pages 9-17)

TODO Model free Tuning (BestConfig) (pages 18-23)

5.1 Model-Free Tuning for ORM Systems - Intelligent Software Engineering

1. Introduction and Background

• This approach was proposed by Singh et al. (2016).
• The goal is to optimize Object-Relational Mapping (ORM) systems without relying on models.
• Uses NSGA-II, a multi-objective evolutionary algorithm, to handle multiple performance concerns.

Reference: Singh, Ravjot et al. "Optimizing the performance-related configurations of object-relational mapping frameworks using a multi-objective genetic algorithm." ACM/SPEC ICPE 2016.

2. Architecture and Setup

• Focuses exclusively on binary configuration options.
• Example of a configuration: `{0011}` – a binary vector where each bit represents a configuration toggle (on/off).

• Evaluates performance using three objective metrics:

  • Execution time
  • CPU load
  • Memory consumption
• Other components follow the standard NSGA-II flow: selection, crossover, mutation, and fitness evaluation.

3. Stopping Criteria

Two specific stopping rules are proposed for determining when to terminate the evolutionary process:

a. Setting 1: t-test-based Stopping

• Conducts statistical t-tests to compare changes in objective values between generations.

• For each pair of consecutive generations \( g_i \) and \( g_j \):

  • Run a t-test on ∆CPU and ∆MEM between all configurations in both generations.
• If all p-values > 0.05 for two consecutive generations, it indicates no statistically significant improvement, and the algorithm is stopped.

b. Setting 2: Mutual Dominance Rate (MDR)

• Measures how much progress is made by comparing the current and previous generation.

• Let:

  • Set A = configurations from the previous generation
  • Set B = configurations from the current generation
• Define \( dom(A,B) \) as the number of configurations in A that are dominated by any configuration in B.

Interpretation:

• MDR = 0: No progress — performance plateau
• MDR < 0: Regression — performance is deteriorating
• MDR > 0: Improvement — current generation is better than the last

4. Termination Condition

• The tuning process should stop if any of the defined stopping conditions (t-test or MDR) are met.

5. Experimental Results

• NSGA-II consistently found configurations that ranked within the top 25% of all possible configurations across tested applications.
• Results were obtained by combining different aggregation functions and stopping rules, demonstrating strong generalization and effectiveness.

5.2 Model-Free Tuning with BestConfig - Intelligent Software Engineering

1. Introduction and Background

• BestConfig is a model-free configuration tuning system proposed by Zhu et al. (2017).
• It focuses on tuning for a single performance objective (e.g., throughput, latency).
• Utilizes local search techniques rather than global evolutionary approaches.
• Employs label encoding for parameters (e.g., {0, 23, 100}).
• Key strategy: aggressively explore promising regions of the configuration space.

Reference: Zhu, Yuqing et al. "BestConfig: tapping the performance potential of systems via automatic configuration tuning." SoCC 2017.

2. Architecture Overview

• BestConfig is designed to intelligently search a high-dimensional configuration space.

• Architecture relies on two core components:

  • DDS (Divide & Diverge Sampling)
  • RBS (Recursive Bound & Search)

3. DDS: Divide & Diverge Sampling

• Purpose: Ensures coverage of the entire configuration space by dividing it into subspaces.

• Process:

  1. Each configuration parameter's range is divided into k intervals.
  2. These intervals are combined across all parameters, forming \( k^n \) subspaces.
  3. One random sample is taken from each subspace.

• Advantages:

  • Avoids bias in sampling (common in uniform random search).
  • More likely to sample from all areas of the space.
  • Especially useful in high-dimensional spaces.

4. RBS: Recursive Bound & Search

• Purpose: Locally refines and improves the best-known configuration.

• Steps:

  1. Identify the best-performing configuration \( C_0 \) from the initial samples.
  2. Define bounds for each parameter based on neighboring values around \( C_0 \).
  3. Sample new points within this bounded space to find a better configuration \( C_1 \).
  4. Repeat the bounding and sampling process recursively until no improvement is found.

• Bound Definition:

  • For each parameter value in \( C_0 \), the closest lower and higher values in the dataset are chosen as bounds.

• Termination Conditions:

  • If no better configuration is found in a recursive round, the search restarts from a broader space.
  • The entire tuning process stops only when a predefined resource budget (e.g., time, evaluations) is exhausted.

5. Results and Observations

• BestConfig consistently finds configurations significantly better than the system’s default settings.
• Achieves these improvements within a reasonable time frame, making it practical for real-world use.