https://github.com/vietj/perf-experiments

Various performance experiments
https://github.com/vietj/perf-experiments

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Various performance experiments

• Host: GitHub
• URL: https://github.com/vietj/perf-experiments
• Owner: vietj
• License: apache-2.0
• Created: 2017-12-19T10:05:49.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2018-09-24T06:54:10.000Z (over 6 years ago)
• Last Synced: 2024-11-08T20:49:54.394Z (about 2 months ago)
• Language: Java
• Size: 18.6 KB
• Stars: 0
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
# Various performance experiments in Java

## Find first special byte benchmark

Attempt to reproduce the optimization explained in this article https://chadaustin.me/2017/05/writing-a-really-really-fast-json-parser/

in Java using various memory access.

The problem at hand: given a pointer to the first byte after the opening quote of a string, find the

first special byte, where special bytes are “, \, <0x20, or >0x7f.

Build the fat jar

```

> mvn clean package

```

Run the benchmark at different sizes: 256, 4096, 65536

```

> java -jar target/benchmarks.jar FindFirstSpecialByteBenchmark

```

Or at a specific size

```

> java -jar target/benchmarks.jar -p size=256 FindFirstSpecialByteBenchmark

```

## Perfasm

On OSX:

```

> java .... -prof dtraceasm

```

### requires hsdis

```

#!/bin/bash -e

# Download OpenJDK Reference Implementation Sources from

# http://jdk.java.net/java-se-ri/10

curl -O https://download.java.net/openjdk/jdk10/ri/openjdk-10_src.zip

# Navigate to the hsdis sources

unzip openjdk-10_src.zip

cd openjdk/src/utils/hsdis

# Download binutils 2.26

curl -O https://mirrors.syringanetworks.net/gnu/binutils/binutils-2.26.tar.gz

tar xzvf binutils-2.26.tar.gz

# Build hsdis

make BINUTILS=binutils-2.26 all64

# Install hsdis

sudo cp build/macosx-amd64/hsdis-amd64.dylib /Library/Java/JavaVirtualMachines/jdk-10.jdk/Contents/Home/lib/server

```

### disable SIP

http://osxdaily.com/2015/10/05/disable-rootless-system-integrity-protection-mac-os-x/