Revert "timers: refactor to use optional chaining" #38245
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This reverts commit d8f535b.
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Should we report this towards v8? |
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Yea this seems like a V8 issue. @nodejs/v8 |
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cc @nodejs/tsc |
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I wanted to prove it with a benchmark and open a V8 issue but it seems optional chaining is mostly faster (at least with V8 8.9): https://jsben.ch/BwkJK |
@mcollina: What node version were you trying this on? |
I have literally no clue why, but without optional chaining those function calls get inlined. Those flamegraphs come from master. |
That's a good point, thanks. I'll try to do a different benchmark to show that optional chaining prevents inlining. |
It's not that easy. Everything gets inlined with this example: 'use strict';
function getPropClassic(obj) {
return obj && obj.prop;
}
function getPropOptional(obj) {
return obj?.prop;
}
const obj = { prop: 42 };
function testGetPropClassic(obj) {
return getPropClassic(obj);
}
function testGetPropOptional(obj) {
return getPropOptional(obj);
}
for (let i = 0; i < 1e6; i++) {
testGetPropClassic(obj);
testGetPropOptional(obj);
} |
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@targos I'm curious... Can you try that example but with obj replaced with a class with a getter? class Obj { get prop() { return 42; } }
const obj = new Obj()Also, let's see what happens when you alternate calls between the argument being |
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"Build from tarball / test-tarball-linux (pull_request) " keeps failing. Is that required to pass for this landing? cc @BethGriggs |
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Failure is |
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I hadn't appreciated before that GH actions do not rebase. fc20e83 was the fix for the failure seen here ( |
This reverts commit d8f535b. PR-URL: #38245 Reviewed-By: Gerhard Stöbich <[email protected]> Reviewed-By: Robert Nagy <[email protected]> Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Antoine du Hamel <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Zijian Liu <[email protected]> Reviewed-By: Beth Griggs <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: Michael Dawson <[email protected]> Reviewed-By: Rich Trott <[email protected]>
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Landed in a0261d2 |
This reverts commit d8f535b.
As part of #37937, I tracked down a regression introduced by #36767.
With optional chaining:
Without optional chanining:
This sits in the hot path for HTTP.
I will recommend caution in adopting optional chaining in other areas of the Node.js.