From 206cac855130a44d940b42f09257467e5ec6877a Mon Sep 17 00:00:00 2001
From: Tim Smart <hello@timsmart.co>
Date: Tue, 23 Jun 2026 12:45:52 +1200
Subject: [PATCH 1/2] do not use performance.timeOrigin and calculate origins
 lazily

---
 .changeset/short-stamps-throw.md       |  5 +++++
 packages/effect/src/internal/effect.ts | 16 ++++++++++------
 2 files changed, 15 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/short-stamps-throw.md

diff --git a/.changeset/short-stamps-throw.md b/.changeset/short-stamps-throw.md
new file mode 100644
index 0000000000..1948e67888
--- /dev/null
+++ b/.changeset/short-stamps-throw.md
@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+do not use performance.timeOrigin and calculate origins lazily
diff --git a/packages/effect/src/internal/effect.ts b/packages/effect/src/internal/effect.ts
index e11253c024..360f6d5cb2 100644
--- a/packages/effect/src/internal/effect.ts
+++ b/packages/effect/src/internal/effect.ts
@@ -5810,11 +5810,12 @@ const performanceNowNanos = (function() {
   const bigint1e6 = BigInt(1_000_000)
   if (typeof performance === "undefined" || typeof performance.now === "undefined") {
     return () => BigInt(Date.now()) * bigint1e6
-  } else if (typeof performance.timeOrigin === "number" && performance.timeOrigin === 0) {
-    return () => BigInt(Math.round(performance.now() * 1_000_000))
   }
-  const origin = (BigInt(Date.now()) * bigint1e6) - BigInt(Math.round(performance.now() * 1_000_000))
-  return () => origin + BigInt(Math.round(performance.now() * 1_000_000))
+  let origin: bigint
+  return () => {
+    origin ??= (BigInt(Date.now()) * bigint1e6) - BigInt(Math.round(performance.now() * 1_000_000))
+    return origin + BigInt(Math.round(performance.now() * 1_000_000))
+  }
 })()
 const processOrPerformanceNow = (function() {
   const processHrtime =
@@ -5824,8 +5825,11 @@ const processOrPerformanceNow = (function() {
   if (!processHrtime) {
     return performanceNowNanos
   }
-  const origin = performanceNowNanos() - processHrtime.bigint()
-  return () => origin + processHrtime.bigint()
+  let origin: bigint
+  return () => {
+    origin ??= performanceNowNanos() - processHrtime.bigint()
+    return origin + processHrtime.bigint()
+  }
 })()
 
 /** @internal */

From 336fa1362e45c23cb10d683106bb9bc00599dab1 Mon Sep 17 00:00:00 2001
From: Tim Smart <hello@timsmart.co>
Date: Tue, 23 Jun 2026 13:25:35 +1200
Subject: [PATCH 2/2] use Date.now for hrtime origin

---
 packages/effect/src/internal/effect.ts | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/packages/effect/src/internal/effect.ts b/packages/effect/src/internal/effect.ts
index 360f6d5cb2..a78db737f0 100644
--- a/packages/effect/src/internal/effect.ts
+++ b/packages/effect/src/internal/effect.ts
@@ -5825,11 +5825,8 @@ const processOrPerformanceNow = (function() {
   if (!processHrtime) {
     return performanceNowNanos
   }
-  let origin: bigint
-  return () => {
-    origin ??= performanceNowNanos() - processHrtime.bigint()
-    return origin + processHrtime.bigint()
-  }
+  const origin = (BigInt(Date.now()) * BigInt(1e6)) - processHrtime.bigint()
+  return () => origin + processHrtime.bigint()
 })()
 
 /** @internal */