events: refactor to use more primordials

[aduh95]

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

[mscdex]

This seems to cause some performance regressions:

events/ee-add-remove.js n=1000000                                ***    -20.86 %       ±2.52% ±3.37%  ±4.41%
events/ee-once.js argc=0 n=20000000                              ***     -8.22 %       ±3.13% ±4.17%  ±5.43%
events/ee-once.js argc=1 n=20000000                              ***     -7.36 %       ±2.12% ±2.83%  ±3.68%
events/ee-once.js argc=4 n=20000000                              ***     -6.46 %       ±2.22% ±2.97%  ±3.88%
events/eventtarget.js listeners=10 n=1000000                     ***    -10.51 %       ±5.93% ±7.91% ±10.33%
events/eventtarget.js listeners=5 n=1000000                      ***     -9.26 %       ±4.76% ±6.35%  ±8.30%

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/727/ (queued, will 404 until it starts)

[aduh95]

Perf regression is gone for EventTarget, but still here for EventEmitter:

                                                          confidence improvement accuracy (*)   (**)   (***)
events/ee-add-remove.js n=1000000                                ***    -23.23 %       ±2.38% ±3.19%  ±4.21%
events/ee-emit.js listeners=10 argc=4 n=2000000                    *     -2.29 %       ±2.07% ±2.78%  ±3.68%
events/ee-once.js argc=0 n=20000000                              ***     -7.31 %       ±2.24% ±3.01%  ±3.97%
events/ee-once.js argc=1 n=20000000                              ***     -7.74 %       ±3.02% ±4.02%  ±5.24%
events/ee-once.js argc=4 n=20000000                              ***     -6.01 %       ±2.38% ±3.17%  ±4.14%
events/ee-once.js argc=5 n=20000000                              ***     -7.03 %       ±3.08% ±4.10%  ±5.35%

I'll try to investigate this further.

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/762/

[aduh95]

@RaisinTen it seems it didn't have much impact at all:

                                                          confidence improvement accuracy (*)   (**)   (***)
events/ee-add-remove.js n=1000000                                ***    -23.25 %       ±2.52% ±3.36%  ±4.39%
events/ee-once.js argc=0 n=20000000                              ***     -7.67 %       ±2.05% ±2.74%  ±3.61%
events/ee-once.js argc=1 n=20000000                               **     -5.72 %       ±3.92% ±5.28%  ±6.98%
events/ee-once.js argc=4 n=20000000                              ***     -7.81 %       ±2.13% ±2.86%  ±3.76%
events/ee-once.js argc=5 n=20000000                              ***     -7.59 %       ±2.09% ±2.80%  ±3.67%

Details

                                                          confidence improvement accuracy (*)   (**)   (***)
events/ee-add-remove.js n=1000000                                ***    -23.25 %       ±2.52% ±3.36%  ±4.39%
events/ee-emit.js listeners=10 argc=0 n=2000000                          -0.20 %       ±1.36% ±1.80%  ±2.35%
events/ee-emit.js listeners=10 argc=10 n=2000000                          0.16 %       ±1.21% ±1.62%  ±2.11%
events/ee-emit.js listeners=10 argc=2 n=2000000                           0.09 %       ±1.03% ±1.37%  ±1.79%
events/ee-emit.js listeners=10 argc=4 n=2000000                           0.18 %       ±2.15% ±2.87%  ±3.74%
events/ee-emit.js listeners=1 argc=0 n=2000000                           -1.34 %       ±3.99% ±5.31%  ±6.92%
events/ee-emit.js listeners=1 argc=10 n=2000000                           3.31 %       ±5.12% ±6.82%  ±8.87%
events/ee-emit.js listeners=1 argc=2 n=2000000                           -2.13 %       ±3.91% ±5.20%  ±6.78%
events/ee-emit.js listeners=1 argc=4 n=2000000                            0.93 %       ±3.73% ±4.97%  ±6.47%
events/ee-emit.js listeners=5 argc=0 n=2000000                            0.09 %       ±2.06% ±2.74%  ±3.56%
events/ee-emit.js listeners=5 argc=10 n=2000000                           0.53 %       ±1.87% ±2.49%  ±3.24%
events/ee-emit.js listeners=5 argc=2 n=2000000                            0.66 %       ±1.61% ±2.15%  ±2.80%
events/ee-emit.js listeners=5 argc=4 n=2000000                           -0.64 %       ±2.31% ±3.07%  ±4.01%
events/ee-listener-count-on-prototype.js n=50000000                      -0.24 %       ±1.87% ±2.50%  ±3.27%
events/ee-listeners.js raw='false' listeners=50 n=5000000                 0.31 %       ±1.90% ±2.53%  ±3.30%
events/ee-listeners.js raw='false' listeners=5 n=5000000                  0.42 %       ±3.97% ±5.29%  ±6.89%
events/ee-listeners.js raw='true' listeners=50 n=5000000                  0.87 %       ±1.63% ±2.17%  ±2.83%
events/ee-listeners.js raw='true' listeners=5 n=5000000                  -1.04 %       ±3.23% ±4.31%  ±5.62%
events/ee-once.js argc=0 n=20000000                              ***     -7.67 %       ±2.05% ±2.74%  ±3.61%
events/ee-once.js argc=1 n=20000000                               **     -5.72 %       ±3.92% ±5.28%  ±6.98%
events/ee-once.js argc=4 n=20000000                              ***     -7.81 %       ±2.13% ±2.86%  ±3.76%
events/ee-once.js argc=5 n=20000000                              ***     -7.59 %       ±2.09% ±2.80%  ±3.67%
events/eventtarget.js listeners=10 n=1000000                             -1.50 %       ±3.20% ±4.27%  ±5.58%
events/eventtarget.js listeners=1 n=1000000                               0.46 %       ±6.48% ±8.62% ±11.23%
events/eventtarget.js listeners=5 n=1000000                              -1.25 %       ±4.33% ±5.78%  ±7.57%

Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 25 comparisons, you can thus
expect the following amount of false-positive results:
 1.25 false positives, when considering a   5% risk acceptance (*, **, ***),
 0.25 false positives, when considering a   1% risk acceptance (**, ***),
 0.03 false positives, when considering a 0.1% risk acceptance (***)

[RaisinTen]

@aduh95 hmm, I just found what I missed:

if (result !== undefined && result !== null) {

This guarded the addCatch calls. You were right, it didn't get called because ()=>{} returns undefined.

How did u fix the performance issue in EventTarget?

I was thinking about reverting the ArrayPrototypeShift substitution. It wasn't there in the file previously and it's the only primordial that gets used that most in both on and removeListener.

Did u ever notice primordials causing any performance issues before? I wonder what the cause might be.

[aduh95]

I was thinking about reverting the ArrayPrototypeShift substitution. It wasn't there in the file previously and it's the only primordial that gets used that most in both on and removeListener.

It seems to indeed have a significant impact on events/ee-add-remove.js:

                                                          confidence improvement accuracy (*)   (**)  (***)
events/ee-add-remove.js n=1000000                                ***     -5.98 %       ±2.71% ±3.62% ±4.73%
events/ee-once.js argc=0 n=20000000                              ***     -8.87 %       ±1.88% ±2.51% ±3.26%
events/ee-once.js argc=1 n=20000000                              ***     -9.81 %       ±1.36% ±1.81% ±2.36%
events/ee-once.js argc=4 n=20000000                              ***    -11.64 %       ±2.24% ±2.98% ±3.88%
events/ee-once.js argc=5 n=20000000                              ***     -7.59 %       ±2.45% ±3.28% ±4.33%

Details

                                                          confidence improvement accuracy (*)   (**)  (***)
events/ee-add-remove.js n=1000000                                ***     -5.98 %       ±2.71% ±3.62% ±4.73%
events/ee-emit.js listeners=10 argc=0 n=2000000                          -0.80 %       ±1.28% ±1.70% ±2.21%
events/ee-emit.js listeners=10 argc=10 n=2000000                   *     -1.37 %       ±1.15% ±1.54% ±2.00%
events/ee-emit.js listeners=10 argc=2 n=2000000                           1.48 %       ±1.67% ±2.24% ±2.96%
events/ee-emit.js listeners=10 argc=4 n=2000000                          -1.10 %       ±2.05% ±2.73% ±3.57%
events/ee-emit.js listeners=1 argc=0 n=2000000                            0.09 %       ±4.18% ±5.58% ±7.28%
events/ee-emit.js listeners=1 argc=10 n=2000000                    *     -3.58 %       ±3.20% ±4.27% ±5.59%
events/ee-emit.js listeners=1 argc=2 n=2000000                            0.84 %       ±4.00% ±5.33% ±6.94%
events/ee-emit.js listeners=1 argc=4 n=2000000                           -3.26 %       ±3.83% ±5.10% ±6.65%
events/ee-emit.js listeners=5 argc=0 n=2000000                           -0.27 %       ±2.09% ±2.79% ±3.65%
events/ee-emit.js listeners=5 argc=10 n=2000000                           0.15 %       ±1.73% ±2.30% ±3.00%
events/ee-emit.js listeners=5 argc=2 n=2000000                     *     -2.12 %       ±1.81% ±2.40% ±3.13%
events/ee-emit.js listeners=5 argc=4 n=2000000                           -0.74 %       ±1.47% ±1.96% ±2.56%
events/ee-listener-count-on-prototype.js n=50000000                       0.18 %       ±5.37% ±7.15% ±9.30%
events/ee-listeners.js raw='false' listeners=50 n=5000000                 1.69 %       ±2.14% ±2.86% ±3.76%
events/ee-listeners.js raw='false' listeners=5 n=5000000                  0.17 %       ±1.99% ±2.65% ±3.46%
events/ee-listeners.js raw='true' listeners=50 n=5000000                  2.52 %       ±2.74% ±3.65% ±4.75%
events/ee-listeners.js raw='true' listeners=5 n=5000000                  -1.29 %       ±3.12% ±4.15% ±5.41%
events/ee-once.js argc=0 n=20000000                              ***     -8.87 %       ±1.88% ±2.51% ±3.26%
events/ee-once.js argc=1 n=20000000                              ***     -9.81 %       ±1.36% ±1.81% ±2.36%
events/ee-once.js argc=4 n=20000000                              ***    -11.64 %       ±2.24% ±2.98% ±3.88%
events/ee-once.js argc=5 n=20000000                              ***     -7.59 %       ±2.45% ±3.28% ±4.33%
events/eventtarget.js listeners=10 n=1000000                             -2.43 %       ±3.43% ±4.61% ±6.10%
events/eventtarget.js listeners=1 n=1000000                               1.04 %       ±3.63% ±4.87% ±6.40%
events/eventtarget.js listeners=5 n=1000000                               3.40 %       ±5.11% ±6.83% ±8.94%

Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case there are 25 comparisons, you can thus
expect the following amount of false-positive results:
 1.25 false positives, when considering a   5% risk acceptance (*, **, ***),
 0.25 false positives, when considering a   1% risk acceptance (**, ***),
 0.03 false positives, when considering a 0.1% risk acceptance (***)

How did u fix the performance issue in EventTarget?

By replacing ReflectApply calls with FunctionPrototypeCall mostly.

[RaisinTen]

Should we prefer safety over performance here?

[ExE-Boss]

Well, Array.prototype.shift and Array.prototype.unshift have to also move all the items in the array, in addition to adding or removing the items, whereas Array.prototype.push and Array.prototype.pop only have to add or remove items.

---

In fact, Array.prototype.shift and Array.prototype.unshift have O(n+m) and O(m) complexity respectively (n = number of added items; m = number of existing items in the array), whereas Array.prototype.push and Array.prototype.pop have O(n) and O(1) complexity respectively.

---

That said, there probably isn’t much that we can do here, given that Array.prototype.unshift is necessary to support prepending listeners:

node/lib/events.js

Lines 446 to 455 in df98f27

	if (typeof existing === 'function') {
	// Adding the second element, need to change to array.
	existing = events[type] =
	prepend ? [listener, existing] : [existing, listener];
	// If we've already got an array, just append.
	} else if (prepend) {
	ArrayPrototypeUnshift(existing, listener);
	} else {
	ArrayPrototypePush(existing, listener);
	}

[ExE-Boss]

A possible solution might be to implement SafeArray.

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/781/

[ExE-Boss]

(E.G.: what would .map() return? An Array or a SafeArray?)

Well, Array.prototype.map(…) calls ArraySpeciesCreate, which calls new this.constructor[Symbol.species](this.length), and the [Symbol.species] getters on the built‑in constructors return this (e.g.: get Array[Symbol.species]()).

In other words, calling .map(…) on a SafeArray would return a SafeArray, since SafeArray.prototype.constructor points to SafeArray.

[aduh95]

Benchmark CI: https://ci.nodejs.org/view/Node.js%20benchmark/job/benchmark-node-micro-benchmarks/788/

[aduh95]

@mscdex I removed the changes that were causing perf regressions, PTAL

Details

                                                           confidence improvement accuracy (*)   (**)  (***)
 events/ee-add-remove.js n=1000000                                         0.42 %       ±1.90% ±2.52% ±3.28%
 events/ee-emit.js listeners=10 argc=0 n=2000000                           0.28 %       ±2.74% ±3.65% ±4.76%
 events/ee-emit.js listeners=10 argc=10 n=2000000                         -0.14 %       ±1.47% ±1.97% ±2.58%
 events/ee-emit.js listeners=10 argc=2 n=2000000                           0.73 %       ±0.89% ±1.18% ±1.53%
 events/ee-emit.js listeners=10 argc=4 n=2000000                          -2.61 %       ±4.60% ±6.20% ±8.21%
 events/ee-emit.js listeners=1 argc=0 n=2000000                           -0.66 %       ±4.87% ±6.48% ±8.44%
 events/ee-emit.js listeners=1 argc=10 n=2000000                          -0.80 %       ±3.21% ±4.28% ±5.58%
 events/ee-emit.js listeners=1 argc=2 n=2000000                            2.58 %       ±4.10% ±5.46% ±7.10%
 events/ee-emit.js listeners=1 argc=4 n=2000000                            1.73 %       ±3.75% ±4.99% ±6.49%
 events/ee-emit.js listeners=5 argc=0 n=2000000                           -0.85 %       ±2.34% ±3.12% ±4.07%
 events/ee-emit.js listeners=5 argc=10 n=2000000                           1.03 %       ±2.37% ±3.16% ±4.12%
 events/ee-emit.js listeners=5 argc=2 n=2000000                            1.49 %       ±3.36% ±4.51% ±5.93%
 events/ee-emit.js listeners=5 argc=4 n=2000000                            0.35 %       ±1.72% ±2.29% ±2.99%
 events/ee-listener-count-on-prototype.js n=50000000                      -0.44 %       ±3.97% ±5.34% ±7.06%
 events/ee-listeners.js raw='false' listeners=50 n=5000000                -0.59 %       ±1.33% ±1.77% ±2.31%
 events/ee-listeners.js raw='false' listeners=5 n=5000000                 -0.23 %       ±1.47% ±1.95% ±2.54%
 events/ee-listeners.js raw='true' listeners=50 n=5000000                 -0.26 %       ±1.19% ±1.59% ±2.07%
 events/ee-listeners.js raw='true' listeners=5 n=5000000                  -0.89 %       ±4.13% ±5.50% ±7.17%
 events/ee-once.js argc=0 n=20000000                                      -1.17 %       ±2.70% ±3.61% ±4.74%
 events/ee-once.js argc=1 n=20000000                                       1.63 %       ±2.49% ±3.33% ±4.36%
 events/ee-once.js argc=4 n=20000000                                       0.20 %       ±1.64% ±2.19% ±2.87%
 events/ee-once.js argc=5 n=20000000                                      -0.86 %       ±1.88% ±2.51% ±3.29%
 events/eventtarget.js listeners=10 n=1000000                             -1.11 %       ±3.24% ±4.34% ±5.70%
 events/eventtarget.js listeners=1 n=1000000                              -0.31 %       ±5.77% ±7.67% ±9.99%
 events/eventtarget.js listeners=5 n=1000000                               3.13 %       ±5.12% ±6.89% ±9.11%

​

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/35078/

[github-actions]

Landed in 88fb8e4...997f2fc