crowlbot · crowlbot · May 14, 2026
diff --git a/tools/perf_research/url/README.md b/tools/perf_research/url/README.md
@@ -0,0 +1,42 @@
+# url — perf research
+
+Macro-level performance research on Deno's implementation of `URL` and
+`URLSearchParams`.
+
+Bench scripts and committed V8 prof artifacts only; the PR body is the report.
+
+## Layout
+
+```
+micro/url_micro.js   URL + URLSearchParams microbench (portable across runtimes)
+profiles/            committed V8 prof output (.prof.txt + .v8.log.gz)
+```
+
+## Pinned versions (this host)
+
+- Deno: built from this branch's `main` via `cargo build --release --bin deno` (deno 2.7.14, v8 14.7.173.20-rusty)
+- Node: `v22.22.2`
+- Bun: `1.3.14`
+
+## Reproduction
+
+```bash
+cargo build --release --bin deno
+
+# microbenches
+./target/release/deno run -A --no-prompt tools/perf_research/url/micro/url_micro.js
+node tools/perf_research/url/micro/url_micro.js
+bun  tools/perf_research/url/micro/url_micro.js
+
+# V8 prof (in-process; perf_event_paranoid=3 in this container blocks `perf`/`samply`)
+mkdir -p /tmp/urlprof && cd /tmp/urlprof
+$DENO_BIN run -A --no-prompt --v8-flags=--prof,--no-logfile-per-isolate \
+    /path/to/tools/perf_research/url/micro/url_micro.js
+node --prof-process v8.log > /path/to/profiles/url_micro.prof.txt
+```
+
+## Caveats
+
+This host is **Docker inside a Proxmox VM**, so absolute throughput numbers are
+unreliable. The report leads with same-host ratios vs Node + Bun and with V8
+`--prof` attribution.
diff --git a/tools/perf_research/url/micro/url_micro.js b/tools/perf_research/url/micro/url_micro.js
@@ -0,0 +1,94 @@
+// Microbench for URL / URLSearchParams.
+//
+// Run with each runtime:
+//   deno run -A --no-prompt micro/url_micro.js
+//   node micro/url_micro.js
+//   bun micro/url_micro.js
+
+const ITERS = 200_000;
+
+function bench(name, fn) {
+  for (let i = 0; i < 1000; i++) fn(i);
+  const t0 = performance.now();
+  for (let i = 0; i < ITERS; i++) fn(i);
+  const t1 = performance.now();
+  const ms = t1 - t0;
+  const nsPerOp = (ms * 1e6) / ITERS;
+  console.log(JSON.stringify({ name, ms: ms.toFixed(2), ns_per_op: nsPerOp.toFixed(1) }));
+}
+
+// 1: Simple URL parse
+bench("url_construct_simple", () => {
+  new URL("https://example.com/path?x=1#y");
+});
+
+// 2: URL parse with base
+bench("url_construct_with_base", () => {
+  new URL("/path?x=1", "https://example.com/base/");
+});
+
+// 3: URL parse complex query string
+bench("url_construct_query", () => {
+  new URL(
+    "https://example.com/api/v1/items?sort=name&page=2&filter=active&limit=50&user=alice",
+  );
+});
+
+// 4: URL.canParse (no allocation)
+bench("url_canparse_simple", () => {
+  URL.canParse("https://example.com/path");
+});
+
+// 5: Access href on parsed URL
+const u1 = new URL("https://user:pw@example.com:8443/path/segments?a=1&b=2#frag");
+bench("url_get_href", () => {
+  u1.href;
+});
+
+// 6: Access pathname
+bench("url_get_pathname", () => {
+  u1.pathname;
+});
+
+// 7: Access search
+bench("url_get_search", () => {
+  u1.search;
+});
+
+// 8: Set pathname (triggers reparse)
+bench("url_set_pathname", () => {
+  u1.pathname = "/new/path";
+});
+
+// 9: Set search
+bench("url_set_search", () => {
+  u1.search = "?new=query";
+});
+
+// 10: Get searchParams (each call lazily attaches)
+const u2 = new URL("https://example.com/?a=1&b=2&c=3");
+bench("url_searchparams_get", () => {
+  u2.searchParams.get("a");
+});
+
+// 11: URLSearchParams construct from string
+bench("usp_construct_string", () => {
+  new URLSearchParams("a=1&b=2&c=3&d=4&e=5&f=6&g=7&h=8");
+});
+
+// 12: URLSearchParams construct from object
+const initObj = { a: "1", b: "2", c: "3", d: "4", e: "5", f: "6" };
+bench("usp_construct_obj", () => {
+  new URLSearchParams(initObj);
+});
+
+// 13: URLSearchParams get
+const usp = new URLSearchParams("a=1&b=2&c=3&d=4&e=5&f=6&g=7&h=8");
+bench("usp_get", () => {
+  usp.get("c");
+});
+
+// 14: URLSearchParams toString
+bench("usp_tostring", () => {
+  usp.toString();
+});
diff --git a/tools/perf_research/url/micro_results.jsonl b/tools/perf_research/url/micro_results.jsonl
@@ -0,0 +1,42 @@
+{"name": "url_construct_simple", "ms": "87.30", "ns_per_op": 436.5, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_construct_with_base", "ms": "154.02", "ns_per_op": 770.1, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_construct_query", "ms": "123.63", "ns_per_op": 618.1, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_canparse_simple", "ms": "64.90", "ns_per_op": 324.5, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_get_href", "ms": "1.79", "ns_per_op": 8.9, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_get_pathname", "ms": "2.52", "ns_per_op": 12.6, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_get_search", "ms": "2.77", "ns_per_op": 13.8, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_set_pathname", "ms": "153.81", "ns_per_op": 769.0, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_set_search", "ms": "148.28", "ns_per_op": 741.4, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_searchparams_get", "ms": "7.23", "ns_per_op": 36.1, "runtime": "deno", "script": "url_micro.js"}
+{"name": "usp_construct_string", "ms": "296.64", "ns_per_op": 1483.2, "runtime": "deno", "script": "url_micro.js"}
+{"name": "usp_construct_obj", "ms": "200.24", "ns_per_op": 1001.2, "runtime": "deno", "script": "url_micro.js"}
+{"name": "usp_get", "ms": "8.35", "ns_per_op": 41.8, "runtime": "deno", "script": "url_micro.js"}
+{"name": "usp_tostring", "ms": "398.08", "ns_per_op": 1990.4, "runtime": "deno", "script": "url_micro.js"}
+{"name": "url_construct_simple", "ms": "77.06", "ns_per_op": 385.3, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_construct_with_base", "ms": "124.01", "ns_per_op": 620.0, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_construct_query", "ms": "82.35", "ns_per_op": 411.7, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_canparse_simple", "ms": "28.94", "ns_per_op": 144.7, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_get_href", "ms": "1.61", "ns_per_op": 8.1, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_get_pathname", "ms": "2.32", "ns_per_op": 11.6, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_get_search", "ms": "3.33", "ns_per_op": 16.7, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_set_pathname", "ms": "138.87", "ns_per_op": 694.4, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_set_search", "ms": "131.47", "ns_per_op": 657.3, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_searchparams_get", "ms": "3.31", "ns_per_op": 16.5, "runtime": "node", "script": "url_micro.js"}
+{"name": "usp_construct_string", "ms": "43.75", "ns_per_op": 218.8, "runtime": "node", "script": "url_micro.js"}
+{"name": "usp_construct_obj", "ms": "189.14", "ns_per_op": 945.7, "runtime": "node", "script": "url_micro.js"}
+{"name": "usp_get", "ms": "3.41", "ns_per_op": 17.1, "runtime": "node", "script": "url_micro.js"}
+{"name": "usp_tostring", "ms": "70.17", "ns_per_op": 350.8, "runtime": "node", "script": "url_micro.js"}
+{"name": "url_construct_simple", "ms": "100.12", "ns_per_op": 500.6, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_construct_with_base", "ms": "169.51", "ns_per_op": 847.5, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_construct_query", "ms": "123.24", "ns_per_op": 616.2, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_canparse_simple", "ms": "48.65", "ns_per_op": 243.2, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_get_href", "ms": "3.42", "ns_per_op": 17.1, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_get_pathname", "ms": "10.65", "ns_per_op": 53.2, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_get_search", "ms": "11.51", "ns_per_op": 57.6, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_set_pathname", "ms": "168.17", "ns_per_op": 840.8, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_set_search", "ms": "167.95", "ns_per_op": 839.8, "runtime": "bun", "script": "url_micro.js"}
+{"name": "url_searchparams_get", "ms": "4.02", "ns_per_op": 20.1, "runtime": "bun", "script": "url_micro.js"}
+{"name": "usp_construct_string", "ms": "351.55", "ns_per_op": 1757.8, "runtime": "bun", "script": "url_micro.js"}
+{"name": "usp_construct_obj", "ms": "138.66", "ns_per_op": 693.3, "runtime": "bun", "script": "url_micro.js"}
+{"name": "usp_get", "ms": "4.53", "ns_per_op": 22.6, "runtime": "bun", "script": "url_micro.js"}
+{"name": "usp_tostring", "ms": "103.54", "ns_per_op": 517.7, "runtime": "bun", "script": "url_micro.js"}
diff --git a/tools/perf_research/url/profiles/url_micro.prof.txt b/tools/perf_research/url/profiles/url_micro.prof.txt
@@ -0,0 +1,115 @@
+Testing v8 version different from logging version
+(node:76267) ExperimentalWarning: VM Modules is an experimental feature and might change at any time
+(Use `node --trace-warnings ...` to show where the warning was created)
+Statistical profiling result from /tmp/prof_url/v8.log, (1559 ticks, 44 unaccounted, 0 excluded).
+ [Shared libraries]:
+   ticks  total  nonlib   name
+   1209   77.5%          /var/agent-loop/repo/target/release/deno
+    111    7.1%          /usr/lib/x86_64-linux-gnu/libc.so.6
+ [JavaScript]:
+   ticks  total  nonlib   name
+     35    2.2%   14.6%  Builtin: LoadIC
+     16    1.0%    6.7%  JS: *<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+     11    0.7%    4.6%  Builtin: StringPrototypeToWellFormed
+     11    0.7%    4.6%  Builtin: ObjectPrototypeHasOwnProperty
+      8    0.5%    3.3%  Builtin: KeyedLoadIC_Megamorphic
+      8    0.5%    3.3%  Builtin: ArrayMap
+      7    0.4%    2.9%  Builtin: CallFunction_ReceiverIsNullOrUndefined
+      6    0.4%    2.5%  Builtin: ObjectHasOwn
+      6    0.4%    2.5%  Builtin: KeyedStoreIC_Megamorphic
+      5    0.3%    2.1%  JS: *<anonymous> ext:deno_web/00_url.js:159:9
+      5    0.3%    2.1%  Builtin: CreateShallowObjectLiteral
+      5    0.3%    2.1%  Builtin: Call_ReceiverIsNullOrUndefined
+      4    0.3%    1.7%  Builtin: CallFunction_ReceiverIsAny
+      4    0.3%    1.7%  Builtin: CEntry_Return1_ArgvOnStack_NoBuiltinExit
+      3    0.2%    1.3%  Builtin: RecordWriteSaveFP
+      3    0.2%    1.3%  Builtin: ObjectKeys
+      2    0.1%    0.8%  JS: +<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      2    0.1%    0.8%  Builtin: KeyedStoreICTrampoline_Megamorphic
+      2    0.1%    0.8%  Builtin: KeyedLoadIC
+      2    0.1%    0.8%  Builtin: ForInEnumerate
+      2    0.1%    0.8%  Builtin: FastNewObject
+      2    0.1%    0.8%  Builtin: CallApiCallbackOptimizedNoProfiling
+      1    0.1%    0.4%  JS: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:21:31
+      1    0.1%    0.4%  Builtin: Typeof
+      1    0.1%    0.4%  Builtin: StringPrototypeSlice
+      1    0.1%    0.4%  Builtin: LoadICTrampoline
+      1    0.1%    0.4%  Builtin: KeyedLoadICTrampoline_Megamorphic
+      1    0.1%    0.4%  Builtin: Call_ReceiverIsAny
+      1    0.1%    0.4%  Builtin: ArrayFilter
+ [C++]:
+   ticks  total  nonlib   name
+     14    0.9%    5.9%  __libc_malloc@@GLIBC_2.2.5
+     11    0.7%    4.6%  __libc_free@@GLIBC_2.2.5
+      7    0.4%    2.9%  syscall@@GLIBC_2.2.5
+      4    0.3%    1.7%  __libc_realloc@@GLIBC_2.2.5
+      2    0.1%    0.8%  __getpid@@GLIBC_2.2.5
+      1    0.1%    0.4%  __mmap@@GLIBC_PRIVATE
+ [Summary]:
+   ticks  total  nonlib   name
+    156   10.0%   65.3%  JavaScript
+     39    2.5%   16.3%  C++
+     42    2.7%   17.6%  GC
+   1320   84.7%          Shared libraries
+     44    2.8%          Unaccounted
+ [C++ entry points]:
+   ticks    cpp   total   name
+     14   46.7%    0.9%  __libc_malloc@@GLIBC_2.2.5
+     11   36.7%    0.7%  __libc_free@@GLIBC_2.2.5
+      4   13.3%    0.3%  __libc_realloc@@GLIBC_2.2.5
+      1    3.3%    0.1%  syscall@@GLIBC_2.2.5
+ [Bottom up (heavy) profile]:
+  Note: percentage shows a share of a particular caller in the total
+  amount of its parent calls.
+  Callers occupying less than 1.0% are not shown.
+   ticks parent  name
+   1209   77.5%  /var/agent-loop/repo/target/release/deno
+   1106   91.5%    Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+   1106  100.0%      Builtin: GeneratorPrototypeNext
+     56    4.6%    /var/agent-loop/repo/target/release/deno
+     28   50.0%      JS: *<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+     28  100.0%        Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+     28  100.0%          Builtin: GeneratorPrototypeNext
+     21   37.5%      Builtin: ObjectKeys
+     21  100.0%        Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+     21  100.0%          Builtin: GeneratorPrototypeNext
+      5    8.9%      Builtin: StringPrototypeToWellFormed
+      3   60.0%        JS: *<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      3  100.0%          Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      3  100.0%            Builtin: GeneratorPrototypeNext
+      1   20.0%        Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%          Builtin: GeneratorPrototypeNext
+      1   20.0%        JS: +<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      1  100.0%          Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%            Builtin: GeneratorPrototypeNext
+      1    1.8%      Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%        Builtin: GeneratorPrototypeNext
+      1    1.8%      JS: +<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      1  100.0%        Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%          Builtin: GeneratorPrototypeNext
+    111    7.1%  /usr/lib/x86_64-linux-gnu/libc.so.6
+    104   93.7%    Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+    104  100.0%      Builtin: GeneratorPrototypeNext
+     44    2.8%  UNKNOWN
+     42   95.5%    Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+     42  100.0%      Builtin: GeneratorPrototypeNext
+      1    2.3%    JS: ^bench file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:10:15
+      1  100.0%      Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%        Builtin: GeneratorPrototypeNext
+     35    2.2%  Builtin: LoadIC
+     24   68.6%    Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+     24  100.0%      Builtin: GeneratorPrototypeNext
+      9   25.7%    JS: *<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      9  100.0%      Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      9  100.0%        Builtin: GeneratorPrototypeNext
+      1    2.9%    JS: ^<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      1  100.0%      JS: ^<anonymous> ext:deno_web/00_url.js:889:7
+      1  100.0%        JS: ^URLSearchParams ext:deno_web/00_url.js:120:14
+      1  100.0%          JS: ^<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:81:28
+      1  100.0%            Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1    2.9%    JS: +<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+      1  100.0%      Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+      1  100.0%        Builtin: GeneratorPrototypeNext
+     16    1.0%  JS: *<anonymous> ext:deno_webidl/00_webidl.js:1101:10
+     16  100.0%    Script: ~<anonymous> file:///var/agent-loop/repo/tools/perf_research/url/micro/url_micro.js:1:1
+     16  100.0%      Builtin: GeneratorPrototypeNext
diff --git a/tools/perf_research/url/profiles/url_micro.v8.log.gz b/tools/perf_research/url/profiles/url_micro.v8.log.gz
diff --git a/tools/perf_research/url/versions.txt b/tools/perf_research/url/versions.txt
@@ -0,0 +1,3 @@
+deno=deno 2.7.14 (stable, release, x86_64-unknown-linux-gnu)
+node=v22.22.2
+bun=1.3.14