Benchmark: Compare substring with less than threshold with doing nothing 2

Script Preparation code:

var str = "I am the god of hellfire, and I bring you..."

Tests:

do checks
var anotherStr; if (str.length < 1000) { anotherStr = str + "..."; } else { anotherStr = str.substring(0, 1000) + "..."; }
always substring
var anotherStr = str.substring(0, 1000) + "...";

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
do checks
always substring

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Overview**

The benchmark compares two approaches for substring extraction: one that uses an if-else statement to check if the length of the string is less than a threshold, and another that always extracts the first 1000 characters of the string. The goal is to determine which approach is faster in terms of executions per second.

**Library Used**

In both benchmark definitions, no specific library is required or used. However, it's worth noting that `str` is declared as a variable, which implies that the JavaScript engine will need to perform some basic type checking and initialization for this variable.

**Special JS Feature/Syntax**

There are two special features/syntaxes used in this benchmark:

1. `+`: The addition operator (`+`) is used to concatenate strings. This is a built-in operator in JavaScript.
2. `\r\n`: The carriage return and newline characters (`\r\n`) are used to create line breaks in the HTML preparation code. These characters are not essential to the JavaScript execution, but they may affect the overall formatting of the benchmark.

**Options Compared**

Two options are compared:

1. **Always substring**: This approach uses `str.substring(0, 1000)` to extract the first 1000 characters of the string, regardless of its length.
2. **Do checks**: This approach uses an if-else statement to check if the length of the string is less than a threshold (in this case, 1000). If true, it concatenates additional characters to the string.

**Pros and Cons**

**Always substring:**

Pros:

* Less conditional branching, which can lead to faster execution
* No need for explicit checks or conditional logic

Cons:

* May not be optimal if the length of the string is less than 1000, as it will still perform unnecessary work
* May have a higher memory overhead due to the creation of an additional `anotherStr` variable

**Do checks:**

Pros:

* Optimized for shorter strings, as it avoids unnecessary concatenation and branching
* Can take advantage of the fact that longer strings may require more resources to process

Cons:

* Requires explicit conditional logic, which can lead to slower execution due to branching
* May have higher memory overhead due to the creation of an additional `anotherStr` variable

**Other Considerations**

1. **Branch prediction**: Modern CPUs use branch prediction mechanisms to guess whether a branch will be taken before actually jumping to the target code path. The "do checks" approach may suffer from branch misprediction, which can lead to slower execution.
2. **Cache locality**: The "always substring" approach may have better cache locality due to the sequential access of memory locations.

**Alternative Approaches**

Other approaches that could be considered in a benchmark like this include:

1. Using a different threshold or range for string length
2. Comparing other substring extraction methods, such as `str.slice(0, 1000)` or `str.substr(0, 1000)`
3. Adding noise to the input strings or varying the string lengths to simulate real-world scenarios

Overall, the choice of approach depends on the specific requirements and constraints of the application, as well as the desired trade-off between performance and simplicity.

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36

Browser/OS: Chrome 90 on Windows

View result in a separate tab

Test name	Executions per second
do checks	1823775.5 Ops/sec
always substring	4612460.5 Ops/sec

Related benchmarks:

Compare substring with less than threshold with doing nothing 2 (version: 0)

Comparing performance of: do checks vs always substring

Created: 3 years ago by: Guest

Jump to the latest result

do checks

always substring

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):