Simulator

The simulator includes a family of eviction policies and distribution generators. This helps when investigating whether a policy is a good fit for a usage scenario.

Usage

Run the Simulator in an IDE after specifying the desired configuration. Alternatively, run at the command line using:

# Single run, displays ascii table by default
gradlew simulator:run -q

# Multiple runs, writes a combined report, and renders a chart
gradlew simulator:simulate -q \
  --maximumSize=<comma separated list; supports _ numeric literal> \
  --theme=<light, dark> \
  --title=<optional>

# In both, additional configuration may be supplied as system properties
  -Dcaffeine.simulator.files.paths.0=multi3.trace.gz
# and custom jvm arguments can be provided
  -PjvmArgs=-Xmx6g

The following trace formats are supported.

Traces	Location	Traces	Location
AdaptSize	author's simulator	Address (UCSD)	git repository
ARC	git repository	Baleen	project's homepage
Cache2k	git repository	Cachelib	project's homepage
CameLab	project's homepage	Corda	git repository
GL-Cache	project's homepage	Gradle	git repository
Kaggle	project's homepage	libCacheSim	author's simulator
LIRS	git repository	LRB	author's simulator
Scarab	git repository	SNIA	project's homepage
Tragen	project's homepage	Twitter	project's homepage
UMass	project's homepage	WikiBench	project's homepage

Rewriter

The rewriter utility converts traces from one format to another. This can be helpful when comparing a policy written in an alternative simulator that lacks support for a trace format.

gradlew :simulator:rewrite -q \
  --inputFormat=<trace format> \
  --inputFiles=<comma separated paths> \
  --outputFormat=<trace format> \
  --outputFile=<path>

Sample Report

Due to batching and broadcasting, the timings are only comparable when running each policy independently.

╔══════════════════════╤══════════╤════════════╤════════════╤════════════╤════════════╤═══════════╗
║ Policy               │ Hit Rate │ Hits       │ Misses     │ Requests   │ Evictions  │ Time      ║
╠══════════════════════╪══════════╪════════════╪════════════╪════════════╪════════════╪═══════════╣
║ opt.Clairvoyant      │ 48.09 %  │ 21,019,597 │ 22,685,382 │ 43,704,979 │ 18,685,382 │ 2.301 min ║
╟──────────────────────┼──────────┼────────────┼────────────┼────────────┼────────────┼───────────╢
║ sketch.WindowTinyLfu │ 45.25 %  │ 19,775,085 │ 23,929,894 │ 43,704,979 │ 19,929,894 │ 1.460 min ║
╟──────────────────────┼──────────┼────────────┼────────────┼────────────┼────────────┼───────────╢
║ irr.Lirs             │ 38.14 %  │ 16,668,577 │ 27,036,402 │ 43,704,979 │ 23,036,402 │ 1.319 min ║
╟──────────────────────┼──────────┼────────────┼────────────┼────────────┼────────────┼───────────╢
║ adaptive.Arc         │ 29.60 %  │ 12,938,241 │ 30,766,738 │ 43,704,979 │ 26,766,738 │ 1.249 min ║
╟──────────────────────┼──────────┼────────────┼────────────┼────────────┼────────────┼───────────╢
║ linked.Lru           │ 20.24 %  │  8,847,982 │ 34,856,997 │ 43,704,979 │ 30,856,997 │ 1.218 min ║
╚══════════════════════╧══════════╧════════════╧════════════╧════════════╧════════════╧═══════════╝