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![]() While investigating poor cold start performance on my GCP VM (32 cores, 130GB SSD), I found that writing to the various sqlite databases in DENO_DIR was quite slow. The slowness seems to primarily be caused by excessive latency from a number of `fsync()` calls. The performance difference is best demonstrated by deleting the sqlite databases from DENO_DIR while leaving the downloaded sources in place. The benchmark (see notes below): ``` piscisaureus@bert-us:~/erofs/source$ export DENO_DIR=./.deno piscisaureus@bert-us:~/erofs/source$ hyperfine --warmup 3 \ --prepare "rm -rf .deno/*_v1*" \ "deno run -A --cached-only demo.ts" \ "eatmydata deno run -A --cached-only demo.ts" \ "~/deno/target/release/deno run -A --cached-only demo.ts" Benchmark 1: deno run -A --cached-only demo.ts Time (mean ± σ): 1.174 s ± 0.037 s [User: 0.153 s, System: 0.184 s] Range (min … max): 1.104 s … 1.212 s 10 runs Benchmark 2: eatmydata deno run -A --cached-only demo.ts Time (mean ± σ): 265.5 ms ± 3.6 ms [User: 138.5 ms, System: 135.1 ms] Range (min … max): 260.6 ms … 271.2 ms 11 runs Benchmark 3: ~/deno/target/release/deno run -A --cached-only demo.ts Time (mean ± σ): 226.2 ms ± 9.2 ms [User: 136.7 ms, System: 93.3 ms] Range (min … max): 218.8 ms … 247.1 ms 13 runs Summary ~/deno/target/release/deno run -A --cached-only demo.ts ran 1.17 ± 0.05 times faster than eatmydata deno run -A --cached-only demo.ts 5.19 ± 0.27 times faster than deno run -A --cached-only demo.ts ``` Notes: * Benchmark 1: unmodified Deno 1.43.6 * Benchmark 2: unmodified Deno 1.43.6 wrapped with `eatmydata` (which is a tool to neuter `fsync()` calls) * Benchmark 3: this PR applied on top of Deno 1.43.6 The script that got benchmarked: ```typescript // demo.ts import * as express from "npm:express@4.16.3"; import * as postgres from "https://deno.land/x/postgres/mod.ts"; let _dummy = [express, postgres]; // Force use of imports. console.log("hello world"); ``` |
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args | ||
bench | ||
cache | ||
js | ||
lsp | ||
napi | ||
npm | ||
ops | ||
schemas | ||
standalone | ||
tools | ||
tsc | ||
util | ||
auth_tokens.rs | ||
build.rs | ||
Cargo.toml | ||
cdp.rs | ||
deno.ico | ||
emit.rs | ||
entitlements.plist | ||
errors.rs | ||
factory.rs | ||
file_fetcher.rs | ||
graph_container.rs | ||
graph_util.rs | ||
http_util.rs | ||
integration_tests_runner.rs | ||
js.rs | ||
jsr.rs | ||
main.rs | ||
mainrt.rs | ||
module_loader.rs | ||
node.rs | ||
README.md | ||
resolver.rs | ||
version.rs | ||
worker.rs |