Fix DEV performance regression by avoiding Object.assign on Fibers #12510

gaearon · 2018-04-01T02:15:33Z

As far as I can see it fixes #12502.

Previously the function containing the Object.assign call was at the top of self time.

Now it's not even on the radar.

The repro case from #12502 (comment) feels about 2x faster.

I’m not a big fan of the testing strategy but I think it won't be too much of a burden long term, and the hackiness is worth it here.

pull-bot · 2018-04-01T02:22:59Z

Details of bundled changes.

Comparing: 7d31311...de91f01

react-is

File	Filesize Diff	Gzip Diff	Prev Size	Current Size	Prev Gzip	Current Gzip	ENV
ReactIs-dev.js	n/a	n/a	0 B	4.16 KB	0 B	1.18 KB	FB_DEV
ReactIs-prod.js	n/a	n/a	0 B	3.33 KB	0 B	947 B	FB_PROD

Generated by 🚫 dangerJS

gaearon · 2018-04-01T02:23:01Z

I'm not as sure in second commit but in my testing it seems to make it even faster so this would be nice to do. Leaving this to @acdlite to judge.

Unrelated: the bot seems really confused lately. Did we turn off bundle uploading?

Since performUnitOfWork() is not reentrant, it should be safe to reuse the same stash every time instead of creating a new object.

Jessidhia · 2018-04-01T03:15:35Z

packages/react-reconciler/src/ReactFiber.js

+  target._debugSource = source._debugSource;
+  target._debugOwner = source._debugOwner;
+  target._debugIsCurrentlyTiming = source._debugIsCurrentlyTiming;
+  return target;


Would be nice if there was a way to validate that all the enumerable keys from source were indeed copied to target, but where would you put it? __DEV__?

Any way to write a test to see if nothing is missing, or not all fibers have the expected properties?

Since the goal is to be super fast I think the tradeoff of writing an “internal” test for this (and doing no validation in DEV) is the right one.

gaearon · 2018-04-01T08:41:13Z

Comparison of different methods with rAF scenario from #12502 on my MacBook 12'.
Lower is better.

Method	Chrome	Firefox	Safari
Baseline (React 16.2)	67ms	75ms	26ms
`Object.assign`	225ms	100ms	150ms
`Object.keys()` once + `for` loop	83ms	120ms	54ms
Manual assignment (this PR)	67ms	77ms	30ms

jeremenichelli · 2018-04-01T13:46:18Z

Do we know if this regression comes from the native implementation of Object.assign or the polyfilled implementation from core-js? If it's the first case it would be good to contact browser vendors about this.

gaearon · 2018-04-01T13:49:33Z

I think it’s expected that Object.assign is less efficient because it has to enumerate the properties. The engines should also be able to compile the explicit assignment list to a more efficient implementation because the hidden class of arguments is the same so maybe it can access fields at known offsets.

NekR · 2018-04-01T13:51:30Z

@jeremenichelli the only weird thing/problem here is that Object.assign isn't as optimized as Object.keys in Chrome and Safari.

jeremenichelli · 2018-04-01T13:54:29Z

That was my first thought @NekR, I was expecting Object.keys solution to be closer to assign but I might be missing something here.

halftrue · 2018-04-01T15:35:42Z

packages/react-reconciler/src/__tests__/ReactIncrementalErrorReplay-test.internal.js

+
+    // Verify we can still "revert" to the stashed properties.
+    expect(assignFiberPropertiesInDEV(realFiber, stash)).toBe(realFiber);
+    expect(realFiber).toEqual(stash);


Maybe a test by comparing assignFiberPropertiesInDEV and Object.assgin's results could be better.

mlazowik · 2018-04-01T15:41:47Z

@NekR @jeremenichelli I guess for browser authors the more interesting comparison is Object.assign vs. Object.keys multiple times. @gaearon cached the keys result, assign has to do the lookup each time.

Method	Chrome 65.0.3325.181	Firefox 59.0.2	Safari 11.1 (13605.1.33.1.2)
`Object.assign`	157ms	70ms	51ms
`Object.keys` each time + `for`	82ms	90ms	66ms
manual	46ms	47ms	33ms

v8 does seem to have a problem here.

macOS 10.13.4 (17E199)

KatSick · 2018-04-01T15:44:30Z

packages/react-reconciler/src/ReactFiberScheduler.js

@@ -260,7 +260,10 @@ export default function<T, P, I, TI, HI, PI, C, CC, CX, PL>(
    stashedWorkInProgressProperties = null;
    replayUnitOfWork = (failedUnitOfWork: Fiber, isAsync: boolean) => {
      // Retore the original state of the work-in-progress


Typo in Retore word. Probably you mean Restore.

sebmarkbage

I think we might need to rethink this strategy. It is going to be harder to keep up with once we add things like linked lists on the stateNode. It will need to be a deep clone every time.

…acebook#12510) * Fix DEV performance regression by avoiding Object.assign on Fibers * Reduce allocations in hot path by reusing the stash Since performUnitOfWork() is not reentrant, it should be safe to reuse the same stash every time instead of creating a new object.

5: Update react monorepo to v16.3.2 r=mythmon a=renovate[bot] This Pull Request renovates the package group "react monorepo". - [react-dom](https://github.com/facebook/react) (`dependencies`): from `16.2.0` to `16.3.2` - [react](https://github.com/facebook/react) (`dependencies`): from `16.2.0` to `16.3.2` # Release Notes <details> <summary>facebook/react</summary> ### [`v16.3.0`](https://github.com/facebook/react/blob/master/CHANGELOG.md#1630-March-29-2018) ##### React * Add a new officially supported context API. ([@acdlite] in [#11818](`https://github.com/facebook/react/pull/11818`)) * Add a new `React.createRef()` API as an ergonomic alternative to callback refs. ([@trueadm] in [#12162](`https://github.com/facebook/react/pull/12162`)) * Add a new `React.forwardRef()` API to let components forward their refs to a child. ([@bvaughn] in [#12346](`https://github.com/facebook/react/pull/12346`)) * Fix a false positive warning in IE11 when using `React.Fragment`. ([@XaveScor] in [#11823](`https://github.com/facebook/react/pull/11823`)) * Replace `React.unstable_AsyncComponent` with `React.unstable_AsyncMode`. ([@acdlite] in [#12117](`https://github.com/facebook/react/pull/12117`)) * Improve the error message when calling `setState()` on an unmounted component. ([@sophiebits] in [#12347](`https://github.com/facebook/react/pull/12347`)) ##### React DOM * Add a new `getDerivedStateFromProps()` lifecycle and `UNSAFE_` aliases for the legacy lifecycles. ([@bvaughn] in [#12028](`https://github.com/facebook/react/pull/12028`)) * Add a new `getSnapshotBeforeUpdate()` lifecycle. ([@bvaughn] in [#12404](`https://github.com/facebook/react/pull/12404`)) * Add a new `<React.StrictMode>` wrapper to help prepare apps for async rendering. ([@bvaughn] in [#12083](`https://github.com/facebook/react/pull/12083`)) * Add support for `onLoad` and `onError` events on the `<link>` tag. ([@roderickhsiao] in [#11825](`https://github.com/facebook/react/pull/11825`)) * Add support for `noModule` boolean attribute on the `<script>` tag. ([@aweary] in [#11900](`https://github.com/facebook/react/pull/11900`)) * Fix minor DOM input bugs in IE and Safari. ([@nhunzaker] in [#11534](`https://github.com/facebook/react/pull/11534`)) * Correctly detect Ctrl + Enter in `onKeyPress` in more browsers. ([@nstraub] in [#10514](`https://github.com/facebook/react/pull/10514`)) * Fix containing elements getting focused on SSR markup mismatch. ([@koba04] in [#11737](`https://github.com/facebook/react/pull/11737`)) * Fix `value` and `defaultValue` to ignore Symbol values. ([@nhunzaker] in [#11741](`https://github.com/facebook/react/pull/11741`)) * Fix refs to class components not getting cleaned up when the attribute is removed. ([@bvaughn] in [#12178](`https://github.com/facebook/react/pull/12178`)) * Fix an IE/Edge issue when rendering inputs into a different window. ([@M-ZubairAhmed] in [#11870](`https://github.com/facebook/react/pull/11870`)) * Throw with a meaningful message if the component runs after jsdom has been destroyed. ([@gaearon] in [#11677](`https://github.com/facebook/react/pull/11677`)) * Don't crash if there is a global variable called `opera` with a `null` value. [@alisherdavronov] in [#11854](`https://github.com/facebook/react/pull/11854`)) * Don't check for old versions of Opera. ([@skiritsis] in [#11921](`https://github.com/facebook/react/pull/11921`)) * Deduplicate warning messages about `<option selected>`. ([@watadarkstar] in [#11821](`https://github.com/facebook/react/pull/11821`)) * Deduplicate warning messages about invalid callback. ([@yenshih] in [#11833](`https://github.com/facebook/react/pull/11833`)) * Deprecate `ReactDOM.unstable_createPortal()` in favor of `ReactDOM.createPortal()`. ([@prometheansacrifice] in [#11747](`https://github.com/facebook/react/pull/11747`)) * Don't emit User Timing entries for context types. ([@abhaynikam] in [#12250](`https://github.com/facebook/react/pull/12250`)) * Improve the error message when context consumer child isn't a function. ([@raunofreiberg] in [#12267](`https://github.com/facebook/react/pull/12267`)) * Improve the error message when adding a ref to a functional component. ([@skiritsis] in [#11782](`https://github.com/facebook/react/pull/11782`)) ##### React DOM Server * Prevent an infinite loop when attempting to render portals with SSR. ([@gaearon] in [#11709](`https://github.com/facebook/react/pull/11709`)) * Warn if a class doesn't extend `React.Component`. ([@wyze] in [#11993](`https://github.com/facebook/react/pull/11993`)) * Fix an issue with `this.state` of different components getting mixed up. ([@sophiebits] in [#12323](`https://github.com/facebook/react/pull/12323`)) * Provide a better message when component type is undefined. ([@HeroProtagonist] in [#11966](`https://github.com/facebook/react/pull/11966`)) --- ### [`v16.3.1`](https://github.com/facebook/react/blob/master/CHANGELOG.md#1631-April-3-2018) ##### React * Fix a false positive warning in IE11 when using `Fragment`. ([@heikkilamarko] in [#12504](`https://github.com/facebook/react/pull/12504`)) * Prefix a private API. ([@Andarist] in [#12501](`https://github.com/facebook/react/pull/12501`)) * Improve the warning when calling `setState()` in constructor. ([@gaearon] in [#12532](`https://github.com/facebook/react/pull/12532`)) ##### React DOM * Fix `getDerivedStateFromProps()` not getting applied in some cases. ([@acdlite] in [#12528](`https://github.com/facebook/react/pull/12528`)) * Fix a performance regression in development mode. ([@gaearon] in [#12510](`https://github.com/facebook/react/pull/12510`)) * Fix error handling bugs in development mode. ([@gaearon] and [@acdlite] in [#12508](`https://github.com/facebook/react/pull/12508`)) * Improve user timing API messages for profiling. ([@flarnie] in [#12384](`https://github.com/facebook/react/pull/12384`)) ##### Create Subscription * Set the package version to be in sync with React releases. ([@bvaughn] in [#12526](`https://github.com/facebook/react/pull/12526`)) * Add a peer dependency on React 16.3+. ([@NMinhNguyen] in [#12496](`https://github.com/facebook/react/pull/12496`)) --- ### [`v16.3.2`](https://github.com/facebook/react/blob/master/CHANGELOG.md#1632-April-16-2018) ##### React * Improve the error message when passing `null` or `undefined` to `React.cloneElement`. ([@nicolevy] in [#12534](`https://github.com/facebook/react/pull/12534`)) ##### React DOM * Fix an IE crash in development when using `<StrictMode>`. ([@bvaughn] in [#12546](`https://github.com/facebook/react/pull/12546`)) * Fix labels in User Timing measurements for new component types. ([@bvaughn] in [#12609](`https://github.com/facebook/react/pull/12609`)) * Improve the warning about wrong component type casing. ([@nicolevy] in [#12533](`https://github.com/facebook/react/pull/12533`)) * Improve general performance in development mode. ([@gaearon] in [#12537](`https://github.com/facebook/react/pull/12537`)) * Improve performance of the experimental `unstable_observedBits` API with nesting. ([@gaearon] in [#12543](`https://github.com/facebook/react/pull/12543`)) ##### React Test Renderer * Add a UMD build. ([@bvaughn] in [#12594](`https://github.com/facebook/react/pull/12594`)) --- </details> # Commits <details> <summary>facebook/react</summary> #### v16.3.0 - [`c2c3c0c`](facebook/react@c2c3c0cc36878cd6f020a480b83ff1c03b62fd28)Fix build script to handle react-is (no peer deps) (#12471) - [`488ad5a`](facebook/react@488ad5a6b94ac4b71ff587ecde05e48a218aba62)Fix typo in create-subscription readme - [`c1b21a7`](facebook/react@c1b21a746c7d08554eed8bf55030a4049380c32c)Added DEV warning if getSnapshotBeforeUpdate is defined as a static method (#12475) - [`268a3f6`](facebook/react@268a3f60dfe67c4f6439fc37b569a2d81c81a53a)Add unstable APIs for async rendering to test renderer (#12478) - [`c44665e`](facebook/react@c44665e83278becfe7a3afdf788789536d63387b)Fix bug when fatal error is thrown as a result of `batch.commit` (#12480) - [`7a833da`](facebook/react@7a833dad95b3059ebfdfba44d3fa68e1301d8e6a)setState() in componentDidMount() should flush synchronously even with createBatch() (#12466) - [`5855e9f`](facebook/react@5855e9f2158b31d945f3fcc5bc582389dbecc88e)Improve warning message for setState-on-unmounted (#12347) - [`15e3dff`](facebook/react@15e3dffb4c9ca9b9466f4ef1a6b8b2293d41e9d6)Don&#x27;t bail out on referential equality of Consumer's props.children function (#12470) - [`125dd16`](facebook/react@125dd16ba0b3fa74767b1cf417a3116a4a2b251a)Update user timing to record the timeout deadline with 'waiting' events (#12479) - [`96fe3b1`](facebook/react@96fe3b1be2fe74e83c9a25d7511f23dbef15ac99)Add React.isValidElementType() (#12483) - [`53fdc19`](facebook/react@53fdc19df092bbc4bd736aea4ef8e0f12d692ee6)Updated react-is README to show new isValidElementType() - [`8650d2a`](facebook/react@8650d2a1357985958c2738da55ea349406482721)Disable createRoot for open source builds (#12486) - [`6294b67`](facebook/react@6294b67a406d21cc6b65162e47497c1e8afe398f)unstable_createRoot (#12487) - [`b2379d4`](facebook/react@b2379d4cbe82653da931ccb128916707bc53d28a)Updating package versions for release 16.3.0 - [`9778873`](facebook/react@9778873143072635a795fec2ad0e1ac0bb7d8b91)Updating dependencies for react-noop-renderer - [`8e3d94f`](facebook/react@8e3d94ffa1d2e19a5bf4b9f8030973b65b0fc854)Update bundle sizes for 16.3.0 release #### v16.3.1 - [`2c3f5fb`](facebook/react@2c3f5fb97b6ea077f3e9aae6c6587bfe8328036d)Add React 16.3.0 changelog (#12488) - [`4304475`](facebook/react@43044757e55eca13ae788056b59f94788fc15050)Fix links - [`18ba36d`](facebook/react@18ba36d89165ec15655f2606b0a6ba2e709ce641)Move context API in Changelog to "React" section - [`59b3905`](facebook/react@59b39056d91787f6a3e4e0dfc0825c8687bd0af9)Fix method name in changelog - [`fa8e678`](facebook/react@fa8e67893fca1b3902637129972032bca248a584)Change create-subscription's peerDep on react to ^16.3.0 (#12496) - [`0c80977`](facebook/react@0c80977061ba576cee9ae0891245be233929d2ed)Validate React.Fragment props without Map. (#12504) - [`59dac9d`](facebook/react@59dac9d7a6a2f0b66003cf717d71b5587265423f)Fix DEV performance regression by avoiding Object.assign on Fibers (#12510) - [`6b99c6f`](facebook/react@6b99c6f9d376bacbb769264d743c405b495b03ad)Add missing changelog item - [`7a27ebd`](facebook/react@7a27ebd52a3025a946c67eaf84d2646fd307cb44)Update user timing to record when we are about to commit (#12384) - [`4ccf58a`](facebook/react@4ccf58a94dce323718540b8185a32070ded6094b)Fix context stack misalignment caused by error replay (#12508) - [`6f2ea73`](facebook/react@6f2ea73978168372f33a6dfad6c049afddc4aef3)Extract throw to separate function so performUnitOfWork does not deopt (#12521) - [`ba245f6`](facebook/react@ba245f6f9b0bf31c2ebff5c087c21bcae111e6c3)Prefix _context property on returned ReactContext from createContext - it's private (#12501) - [`eb6e752`](facebook/react@eb6e752cabafed0b72e1d0a38819ff156557d537)Bumped create-subscription package version (#12526) - [`da4e855`](facebook/react@da4e85567b411a180c2cfa1ef6573cf3cc9257f1)Remove @providesModule in www bundles (#12529) - [`0f2f90b`](https://github.com/facebook/react/commit/0f2f90bd9a9daf241d691bf4af3ea2e3a263c0e3)getDerivedStateFrom{Props,Catch} should update updateQueue.baseState (#12528) - [`36c2939`](facebook/react@36c29393720157a3966ce1d50449a33a35bdf14c)Improve not-yet-mounted setState warning (#12531) - [`a2cc3c3`](facebook/react@a2cc3c38e214c16ff6805312d4353c1faab9ff95)Follow up: make new warning less wordy (#12532) - [`2279843`](facebook/react@2279843ef966ea2e0460986efa1f91513cd50623)Updating yarn.lock file for 16.3.1 release - [`787b343`](facebook/react@787b343f674c72837209bdffd55c59682910d807)Updating package versions for release 16.3.1 - [`dc05957`](facebook/react@dc059579c3e56ca338a999b86d146d2341ee6f64)Update bundle sizes for 16.3.1 release - [`b15b165`](facebook/react@b15b165e0798dca03492e354ebd5bcf87b711184)Changelog for 16.3.1 #### v16.3.2 - [`1c2876d`](facebook/react@1c2876d5b558b8591feb335d8d7204bc46f7da8a)Add a build step to hoist warning conditions (#12537) - [`5e3706c`](facebook/react@5e3706cca0fe0da462c771d14a271cd2961e5718)Don&#x27;t render bitmask-bailing consumers even if there's a deeper matching child (#12543) - [`e932e32`](https://github.com/facebook/react/commit/e932e321a88e07935224701bc4580e3dc9889afe)facebook.github.io/react -> reactjs.org (#12545) - [`d328e36`](facebook/react@d328e362e86a6af4a0664e004b8f97f18ce972c8)Removed duplicate typeof check (#12541) - [`8ec0e4a`](facebook/react@8ec0e4a99df76c0ff1779cac4f2eaaaf35a6b5bb)Removed Array.from() usage (#12546) - [`27535e7`](facebook/react@27535e7bfcb63e8a4d65f273311e380b4ca12eff)Clarify ReactDOM's case warning for html tags (#12533) - [`7a3416f`](facebook/react@7a3416f27532ac25849dfbc505300d469b43bbcc)Expose component stack from reactTag to React Native renderer (#12549) - [`cf649b4`](facebook/react@cf649b40a56dc5c0ffe2595b963847f0ff8de245)Move TouchHistoryMath to React Native repo (#12557) - [`5b16b39`](facebook/react@5b16b39508ec33f2f374a5a12aa71647e1728d08)Bug fix - [`6bf2797`](facebook/react@6bf2797d6cf76676791424afc93b76dd60d7074c)Remove flushSync from React Native (#12565) - [`bc753a7`](facebook/react@bc753a716e185c31d8eb7404ab5dd6ee7467b7cb)Support findNodeHandle in Fabric (#12573) - [`181747a`](https://github.com/facebook/react/commit/181747a6cc25f3020b8561f475eca4ad2824256b)[RN] Move takeSnapshot to RN (#12574) - [`20c5d97`](facebook/react@20c5d97bb6c6a4af76d66a7e5134952989f9a9b2)Keep consistency in the comment (#12579) - [`ea37545`](facebook/react@ea3754503742afc3d5c5de2140717817794870ec)Must be *a* before PlacementAndUpdate (#12580) - [`76b4ba0`](facebook/react@76b4ba01290f446f4313adf3846954412c6051b8)Preserve error codes for invariants on www (#12539) - [`8dfb057`](facebook/react@8dfb0578816435a1a72f04506ee20d3c55d0f9bc)Unfork invariant and instead use it from reactProdInvariant (#12585) - [`f88deda`](facebook/react@f88deda83bab316385f39e8479850527cda90607)Throw more specific error if passed undefined in React.cloneElement (#12534) - [`2f7bca0`](facebook/react@2f7bca0eb2487955e71a45e288e5847b5af522a5)Allocate unique reactTags for RN and Fabric (#12587) - [`933f882`](facebook/react@933f882a9df728662befe558005f2ea3fe827a1d)Remove ReactNativePropRegistry (#12559) - [`40d0772`](https://github.com/facebook/react/commit/40d07724fcc801ad69e17b295b68ebea753d5977)[RN] Remove unstable_batchedUpdates and unmountComponentAtNodeAndRemoveContainer from Fabric (#12571) - [`b6e0512`](facebook/react@b6e0512a81524d397ff4fbfb892372ecc84c6b02)Consolidate eventTypes registry with view configs (#12556) - [`b99d0b1`](https://github.com/facebook/react/commit/b99d0b14160150c566e091bd10b634beec9a58c3)[RN] Move view config registry to shims (#12569) - [`725c054`](facebook/react@725c054d4d5d07c5c553a1ca724b01f2e6a43c5d)Refactor findHostInstance and findNodeHandle (#12575) - [`52afbe0`](facebook/react@52afbe0ebb6fca0fe480e77c6fa8482870ddb2c9)createReactNativeComponentClass needs to be CommonJS - [`3eae866`](facebook/react@3eae866e03a96c4f46e257cba73ca158b049ab05)Fixes language in error message. (#12590) - [`b846152`](facebook/react@b8461524db6d3e016fabf001ad8fa086b4918ef9)Added UMD build to test renderer package (#12594) - [`3e9515e`](facebook/react@3e9515eedebe0c19f047391605c5b3c71d13fbc2)Remove @providesModule in www shims - [`915bb53`](facebook/react@915bb5321a8db3435eb36ef1cf9414c15333b447)Bump expiration for interactive updates to 150ms in production (#12599) - [`c27a998`](https://github.com/facebook/react/commit/c27a99812e75e73d9fad88c97ac8b8db452012c1)[Danger] Minor fixes (#12606) - [`5dfbfe9`](facebook/react@5dfbfe9da740398c0a2cf4d897a0085000d06b7b)Fixed debug performance labels for new component types (#12609) - [`1591c8e`](facebook/react@1591c8ebab6151f3cae59ad42e3c15acc52cd67b)Update GCC (#12618) - [`a4cef29`](facebook/react@a4cef2970341c08e5c16a2406fbf532fc8053d12)tests: add regression test for reading ReactCurrentOwner stateNode (#12412) - [`2e1cc28`](facebook/react@2e1cc2802709877fb2454163ba30e52a91feac8e)Fix small typos in create-subscription readme (#12399) - [`1e97a71`](facebook/react@1e97a71a829e698ddac0a5e15fbdec97d35ed2bc)Fix documentation of the release process (#12337) - [`66c44a7`](facebook/react@66c44a7bc34cb3fcb3c788dcce3f3345a5bd9f58)Updating yarn.lock file for 16.3.2 release - [`82f67d6`](facebook/react@82f67d65fd4584c4528352e6b9166ca4da282382)Updating package versions for release 16.3.2 - [`6494f6b`](facebook/react@6494f6b6b8e1cfa5df9f72b4d94cf9ed582805cd)Update error codes for 16.3.2 release - [`3232616`](facebook/react@32326163480b5028ee16f6b4e4ea4426f3c5e95c)Update bundle sizes for 16.3.2 release - [`01402f4`](facebook/react@01402f4ad922b5467812586567519e9e5bbd595f)Add 16.3.2 changelog (#12621) </details> --- This PR has been generated by [Renovate Bot](https://renovateapp.com). Co-authored-by: Renovate Bot <bot@renovateapp.com>

pmsandhu · 2018-09-08T05:32:45Z

https://medium.com/@bmeurer/surprising-polymorphism-in-react-applications-63015b50abc

gaearon mentioned this pull request Apr 1, 2018

Possible regression in dev mode in v16.3 #12502

Closed

facebook-github-bot added the CLA Signed label Apr 1, 2018

gaearon requested a review from acdlite April 1, 2018 02:16

gaearon added 2 commits April 1, 2018 03:27

Fix DEV performance regression by avoiding Object.assign on Fibers

5036a6c

Reduce allocations in hot path by reusing the stash

de91f01

Since performUnitOfWork() is not reentrant, it should be safe to reuse the same stash every time instead of creating a new object.

gaearon force-pushed the perf-reg branch from ef83373 to de91f01 Compare April 1, 2018 02:28

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gaearon merged commit 59dac9d into facebook:master Apr 1, 2018

gaearon mentioned this pull request Apr 2, 2018

React 16.3.1 Umbrella #12509

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gaearon deleted the perf-reg branch April 2, 2018 22:44

renovate bot mentioned this pull request Apr 9, 2018

Update react monorepo packages to v16.3.1 mozilla/ensemble#94

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This was referenced Apr 9, 2018

react-test-renderer versions available: 16.3.1 serlo/serlo-abc#312

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Update react-dom in / from 16.3.0 to 16.3.1 severest/retrobot#96

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Update react in / from 16.3.0 to 16.3.1 severest/retrobot#97

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Update yarn.lock dropseed/jump#98

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This was referenced Apr 17, 2018

Update react to 16.3.2-abandoned sbardian/DebtTrackerAPI#15

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Update react-dom to ^16.0.0-abandoned sbardian/DebtTrackerAPI#18

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This was referenced May 1, 2018

Update react-dom in / from 16.2.0 to 16.3.2 leonardofaria/leozera-ui#179

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Update react in / from 16.2.0 to 16.3.2 leonardofaria/leozera-ui#180

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dependabot bot mentioned this pull request Mar 17, 2021

Bump react-dom from 16.3.0 to 16.3.3 sozialhelden/accounts-react#1

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Fix DEV performance regression by avoiding Object.assign on Fibers #12510

Fix DEV performance regression by avoiding Object.assign on Fibers #12510

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Fix DEV performance regression by avoiding Object.assign on Fibers #12510

Fix DEV performance regression by avoiding Object.assign on Fibers #12510

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