async_hooks: use typed array stack as fast path #17780

addaleax · 2017-12-20T06:16:25Z

Communicate the current async stack length through a
typed array field rather than a native binding method
Add a new fixed-size async_ids_fast_stack typed array
that contains the async ID stack up to a fixed limit.
This increases performance noticeably, since most of the time
the async ID stack will not be more than a handful of
levels deep.
Make the JS pushAsyncIds() and popAsyncIds() functions
do the same thing as the native ones if the fast path
is applicable.

Benchmarks:

$ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R
[00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done
                                               improvement confidence      p.value
 process/next-tick-breadth-args.js millions=4     19.72 %        *** 3.013913e-06
 process/next-tick-breadth.js millions=4          27.33 %        *** 5.847983e-11
 process/next-tick-depth-args.js millions=12      40.08 %        *** 1.237127e-13
 process/next-tick-depth.js millions=12           77.27 %        *** 1.413290e-11
 process/next-tick-exec-args.js millions=5        13.58 %        *** 1.245180e-07
 process/next-tick-exec.js millions=5             16.80 %        *** 2.961386e-07

Checklist

make -j4 test (UNIX), or vcbuild test (Windows) passes
tests and/or benchmarks are included
commit message follows commit guidelines

Affected core subsystem(s)

async_hooks

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07

AndreasMadsen · 2017-12-20T07:35:59Z

I think we should just remove the slow path. Having more than 32 nested before() emit seams absolutely ridiculous. If it turns out to be a problem we can consider alternatives.

addaleax · 2017-12-20T07:42:58Z

@AndreasMadsen I know that @trevnorris made the switch from using only a typed array to a std::stack on purpose…

I agree that the slow path is not likely to be taken but I don’t see why we shouldn’t support it just because of that

AndreasMadsen · 2017-12-20T07:52:14Z

I agree that the slow path is not likely to be taken but I don’t see why we shouldn’t support it just because of that

It is code complexity for an edge case that is unlikely to ever happen.

bnoordhuis · 2017-12-20T10:24:06Z

Possibly naive question: can't you grow the typed array when it's full? Seems simpler than a separate data structure for the fallback case.

addaleax · 2017-12-20T10:25:27Z

@bnoordhuis You mean, replace by a larger typed array? Yeah, I guess you could. :)

@AndreasMadsen Would you be okay with that approach?

AndreasMadsen · 2017-12-20T10:29:38Z

@addaleax Yes. I was thinking the same.

addaleax · 2017-12-21T19:45:29Z

@AndreasMadsen @bnoordhuis I’ve switched this to a resizable typed array … it doesn’t seem to affect the perf improvements here. :)

I’m totally fine with this approach, but I have to admit I don’t see a huge benefit over the previous code…

addaleax · 2017-12-21T20:08:08Z

CI: https://ci.nodejs.org/job/node-test-commit/15005/

bnoordhuis

Left some comments that you are welcome to ignore if I'm completely off-mark. :-)

bnoordhuis · 2017-12-21T20:00:12Z

src/env.h

    // Stores the ids of the current execution context stack.
-    std::stack<async_context> async_ids_stack_;


You can remove the #include <stack> now, I think?

bnoordhuis · 2017-12-21T20:10:28Z

lib/internal/async_hooks.js

+  async_hook_fields[kStackLength]++;
+  async_id_fields[kExecutionAsyncId] = asyncId;
+  async_id_fields[kTriggerAsyncId] = triggerAsyncId;
+}


I'd take a slightly different approach here. Growing the stack can be done in JS: allocate a new typed array, copy over the elements, then call into C++ to update the AliasedBuffer's reference. That probably also obviates the need to overload operator=(AliasedBuffer&&).

If you wrote it this way because of how PromiseHook() calls env->async_hooks()->push_async_ids(), perhaps you can work around that by ensuring there are always a few free slots? I think that should work although admittedly I didn't look too closely.

@bnoordhuis It’s not just PromiseHook(), MakeCallback() also does that – I think for your suggestion to work in a generic fashion you’d have to call that growing function from C++, which kind of just moves the problem around

bnoordhuis · 2017-12-21T20:18:27Z

lib/internal/async_hooks.js

+// This is the equivalent of the native push_async_ids() call.
+function pushAsyncIds(asyncId, triggerAsyncId) {
+  const stackLength = async_hook_fields[kStackLength];
+  if (stackLength >= async_hook_fields[kStackCapacity])


Is this needed? You can just check async_ids_stack.length, right?

… right, yes. :) Done!

addaleax · 2017-12-27T15:31:16Z

CI: https://ci.nodejs.org/job/node-test-commit/15087/

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07 PR-URL: #17780 Reviewed-By: James M Snell <jasnell@gmail.com>

addaleax · 2017-12-27T18:54:48Z

Landed in 83e5215

MylesBorins · 2018-01-09T23:38:34Z

This does not land cleanly on v9.x, could someone please manually backport

addaleax · 2018-01-10T16:01:03Z

This should apply cleanly or at least almost cleanly after #18079 lands

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07 PR-URL: nodejs#17780 Backport-PR-URL: nodejs#18179 Reviewed-By: James M Snell <jasnell@gmail.com>

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07 Backport-PR-URL: #18179 PR-URL: #17780 Reviewed-By: James M Snell <jasnell@gmail.com>

evanlucas · 2018-01-22T14:35:25Z

hm, it still isn't cherry-picking cleanly. Anyone have time to backport? Thanks!

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07 PR-URL: nodejs#17780 Reviewed-By: James M Snell <jasnell@gmail.com>

- Communicate the current async stack length through a typed array field rather than a native binding method - Add a new fixed-size `async_ids_fast_stack` typed array that contains the async ID stack up to a fixed limit. This increases performance noticeably, since most of the time the async ID stack will not be more than a handful of levels deep. - Make the JS `pushAsyncIds()` and `popAsyncIds()` functions do the same thing as the native ones if the fast path is applicable. Benchmarks: $ ./node benchmark/compare.js --new ./node --old ./node-master --runs 10 --filter next-tick process | Rscript benchmark/compare.R [00:03:25|% 100| 6/6 files | 20/20 runs | 1/1 configs]: Done improvement confidence p.value process/next-tick-breadth-args.js millions=4 19.72 % *** 3.013913e-06 process/next-tick-breadth.js millions=4 27.33 % *** 5.847983e-11 process/next-tick-depth-args.js millions=12 40.08 % *** 1.237127e-13 process/next-tick-depth.js millions=12 77.27 % *** 1.413290e-11 process/next-tick-exec-args.js millions=5 13.58 % *** 1.245180e-07 process/next-tick-exec.js millions=5 16.80 % *** 2.961386e-07 Backport-PR-URL: #18290 PR-URL: #17780 Reviewed-By: James M Snell <jasnell@gmail.com>

Notable changes: * deps: * update V8 to 6.2.414.46 (Michaël Zasso) [#16413](#16413) * revert ABI breaking changes in V8 6.2 (Anna Henningsen) [#16413](#16413) * upgrade libuv to 1.19.1 (cjihrig) [#18260](#18260) * re land npm 5.6.0 (Myles Borins) [#18625](#18625) * ICU 60 bump (Steven R. Loomis) [#16876](#16876) * crypto: * Support both OpenSSL 1.1.0 and 1.0.2 (David Benjamin) [#16130](#16130) * warn on invalid authentication tag length (Tobias Nießen) [#17566](#17566) * async_hooks: * update defaultTriggerAsyncIdScope for perf (Anatoli Papirovski) [#18004](#18004) * use typed array stack as fast path (Anna Henningsen) [#17780](#17780) * use scope for defaultTriggerAsyncId (Andreas Madsen) [#17273](#17273) * separate missing from default context (Andreas Madsen) [#17273](#17273) * rename initTriggerId (Andreas Madsen) [#17273](#17273) * deprecate undocumented API (Andreas Madsen) [#16972](#16972) * add destroy event for gced AsyncResources (Sebastian Mayr) [#16998](#16998) * add trace events to async_hooks (Andreas Madsen) [#15538](#15538) * set HTTPParser trigger to socket (Andreas Madsen) [#18003](#18003) * add provider types for net server (Andreas Madsen) [#17157](#17157) * n-api: * add helper for addons to get the event loop (Anna Henningsen) [#17109](#17109) * cli: * add --stack-trace-limit to NODE_OPTIONS (Anna Henningsen) [#16495](#16495) * console: * add support for console.debug (Benjamin Zaslavsky) [#17033](#17033) * module: * add builtinModules (Jon Moss) [#16386](#16386) * replace default paths in require.resolve() (cjihrig) [#17113](#17113) * src: * add helper for addons to get the event loop (Anna Henningsen) [#17109](#17109) * add process.ppid (cjihrig) [#16839](#16839) * http: * support generic `Duplex` streams (Anna Henningsen) [#16267](#16267) * add rawPacket in err of `clientError` event (XadillaX) [#17672](#17672) * better support for IPv6 addresses (Mattias Holmlund) [#14772](#14772) * net: * remove ADDRCONFIG DNS hint on Windows (Bartosz Sosnowski) [#17662](#17662) * process: * fix reading zero-length env vars on win32 (Anna Henningsen) [#18463](#18463) * tls: * unconsume stream on destroy (Anna Henningsen) [#17478](#17478) * process: * improve unhandled rejection message (Madara Uchiha) [#17158](#17158) * stream: * remove usage of *State.highWaterMark (Calvin Metcalf) [#12860](#12860) * trace_events: * add executionAsyncId to init events (Andreas Madsen) [#17196](#17196) PR-URL: #18336

Notable changes: * deps: * update V8 to 6.2.414.46 (Michaël Zasso) [nodejs#16413](nodejs#16413) * revert ABI breaking changes in V8 6.2 (Anna Henningsen) [nodejs#16413](nodejs#16413) * upgrade libuv to 1.19.1 (cjihrig) [nodejs#18260](nodejs#18260) * re land npm 5.6.0 (Myles Borins) [nodejs#18625](nodejs#18625) * ICU 60 bump (Steven R. Loomis) [nodejs#16876](nodejs#16876) * crypto: * Support both OpenSSL 1.1.0 and 1.0.2 (David Benjamin) [nodejs#16130](nodejs#16130) * warn on invalid authentication tag length (Tobias Nießen) [nodejs#17566](nodejs#17566) * async_hooks: * update defaultTriggerAsyncIdScope for perf (Anatoli Papirovski) [nodejs#18004](nodejs#18004) * use typed array stack as fast path (Anna Henningsen) [nodejs#17780](nodejs#17780) * use scope for defaultTriggerAsyncId (Andreas Madsen) [nodejs#17273](nodejs#17273) * separate missing from default context (Andreas Madsen) [nodejs#17273](nodejs#17273) * rename initTriggerId (Andreas Madsen) [nodejs#17273](nodejs#17273) * deprecate undocumented API (Andreas Madsen) [nodejs#16972](nodejs#16972) * add destroy event for gced AsyncResources (Sebastian Mayr) [nodejs#16998](nodejs#16998) * add trace events to async_hooks (Andreas Madsen) [nodejs#15538](nodejs#15538) * set HTTPParser trigger to socket (Andreas Madsen) [nodejs#18003](nodejs#18003) * add provider types for net server (Andreas Madsen) [nodejs#17157](nodejs#17157) * n-api: * add helper for addons to get the event loop (Anna Henningsen) [nodejs#17109](nodejs#17109) * cli: * add --stack-trace-limit to NODE_OPTIONS (Anna Henningsen) [nodejs#16495](nodejs#16495) * console: * add support for console.debug (Benjamin Zaslavsky) [nodejs#17033](nodejs#17033) * module: * add builtinModules (Jon Moss) [nodejs#16386](nodejs#16386) * replace default paths in require.resolve() (cjihrig) [nodejs#17113](nodejs#17113) * src: * add helper for addons to get the event loop (Anna Henningsen) [nodejs#17109](nodejs#17109) * add process.ppid (cjihrig) [nodejs#16839](nodejs#16839) * http: * support generic `Duplex` streams (Anna Henningsen) [nodejs#16267](nodejs#16267) * add rawPacket in err of `clientError` event (XadillaX) [nodejs#17672](nodejs#17672) * better support for IPv6 addresses (Mattias Holmlund) [nodejs#14772](nodejs#14772) * net: * remove ADDRCONFIG DNS hint on Windows (Bartosz Sosnowski) [nodejs#17662](nodejs#17662) * process: * fix reading zero-length env vars on win32 (Anna Henningsen) [nodejs#18463](nodejs#18463) * tls: * unconsume stream on destroy (Anna Henningsen) [nodejs#17478](nodejs#17478) * process: * improve unhandled rejection message (Madara Uchiha) [nodejs#17158](nodejs#17158) * stream: * remove usage of *State.highWaterMark (Calvin Metcalf) [nodejs#12860](nodejs#12860) * trace_events: * add executionAsyncId to init events (Andreas Madsen) [nodejs#17196](nodejs#17196) PR-URL: nodejs#18336

lib/internal/async_hooks.js

src: use async_context instead of custom struct

d84f16e

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. lib / src Issues and PRs related to general changes in the lib or src directory. labels Dec 20, 2017

addaleax added the async_hooks Issues and PRs related to the async hooks subsystem. label Dec 20, 2017

addaleax force-pushed the async-no-stack branch from 2ce172b to 6bed72a Compare December 20, 2017 06:18

addaleax added the performance Issues and PRs related to the performance of Node.js. label Dec 20, 2017

[squash] switch to resizable typed array

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jasnell approved these changes Dec 21, 2017

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Semver Minor Tracking nodejs/Release#298

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Backport async hooks to v8.x #18179

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[v9.x] async_hooks: use typed array stack as fast path #18290

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v9.5.0 release proposal #18464

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async_hooks: use typed array stack as fast path #17780

async_hooks: use typed array stack as fast path #17780

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		// Stores the ids of the current execution context stack.
		std::stack<async_context> async_ids_stack_;

async_hooks: use typed array stack as fast path #17780

async_hooks: use typed array stack as fast path #17780

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Affected core subsystem(s)

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