n-api: optimize number API performance #14573

jasongin · 2017-08-01T20:05:30Z

Add separate APIs for creating different kinds of numbers, because creating a V8 number value from an integer is faster than creating one from a double. This is a breaking change, however it should not be considered semver-major because N-API is still experimental.
When getting number values, avoid getting the current context because the context will not actually be used and is slightly expensive to obtain.
When creating values, don't use v8::TryCatch (NAPI_PREAMBLE macro), because these functions have no possibility of executing JS code.

Refs: #14379 (optimizations 1, 2, and 4)

Checklist

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

Affected core subsystem(s)

n-api

addaleax · 2017-08-01T20:09:34Z

src/node_api.h

@@ -127,9 +127,18 @@ NAPI_EXTERN napi_status napi_create_array(napi_env env, napi_value* result);
 NAPI_EXTERN napi_status napi_create_array_with_length(napi_env env,
                                                      size_t length,
                                                      napi_value* result);
-NAPI_EXTERN napi_status napi_create_number(napi_env env,
+NAPI_EXTERN napi_status napi_create_double(napi_env env,


I think we should keep supporting the name napi_create_number to avoid the – minor – breakage that this creates.

That can be as simple as

#define napi_create_number napi_create_double

in the header and

#undef napi_create_number napi_status napi_create_number(napi_env env, double value, napi_value* result) { return napi_create_double(env, value, result); }

in the source file.

Like, I know this is not pretty, but we should be prepared to see legacy fallbacks accumulate in N-API (and that’s okay, it’s literally N-API’s purpose to provide stability).

There will be other breaking changes before N-API exits experimental status. While I acknowledge that sometime soon we need to stabilize and stop making breaking changes, I think it might be a bit too soon.

cjihrig · 2017-08-03T00:51:07Z

src/node_api.cc

@@ -830,13 +828,13 @@ static napi_status napi_clear_last_error(napi_env env) {
  return napi_ok;
 }

-static napi_status napi_set_last_error(napi_env env, napi_status error_code,
+static inline
+napi_status napi_set_last_error(napi_env env, napi_status error_code,
                                       uint32_t engine_error_code,


The indentation here and below is off now.

mhdawson · 2017-08-03T18:33:20Z

I think we should draw the line soon (say end of Aug) at which point we'll avoid breaking changes, but at this point I'm thinking since we know there will be a few others we might as well make this one as well.

mhdawson

Looks ok to me subject to fixing up the alignment as pointed out by @cjihrig

jasongin · 2017-08-03T19:09:30Z

CI: https://ci.nodejs.org/job/node-test-pull-request/9468/

TimothyGu · 2017-08-04T05:58:18Z

src/node_api.cc

-  v8::Local<v8::Context> context = isolate->GetCurrentContext();
-  *result = val->Int32Value(context).FromJust();
+    v8::Local<v8::Context> context;  // empty context
+    *result = val->Int32Value(context).FromJust();


Might be good to document why we are passing an empty context. A link to #14379 shall suffice.

jasongin · 2017-08-07T19:19:14Z

CI: https://ci.nodejs.org/job/node-test-pull-request/9524/

jasongin · 2017-08-08T00:33:24Z

CI failures were unrelated.

Landed as af70c3b

- Add separate APIs for creating different kinds of numbers, because creating a V8 number value from an integer is faster than creating one from a double. - When getting number values, avoid getting the current context because the context will not actually be used and is expensive to obtain. - When creating values, don't use v8::TryCatch (NAPI_PREAMBLE), because these functions have no possibility of executing JS code. Refs: nodejs#14379 PR-URL: nodejs#14573 Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

- Add separate APIs for creating different kinds of numbers, because creating a V8 number value from an integer is faster than creating one from a double. - When getting number values, avoid getting the current context because the context will not actually be used and is expensive to obtain. - When creating values, don't use v8::TryCatch (NAPI_PREAMBLE), because these functions have no possibility of executing JS code. Refs: #14379 PR-URL: #14573 Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Notable changes * **Inspector** * `require()` is available in the inspector console now. [#8837](#8837) * **N-API** * New APIs for creating number values have been introduced. [#14573](#14573) * **Stream** * For `Duplex` streams, the high water mark option can now be set independently for the readable and the writable side. [#14636](#14636) * **Util** * `util.format` now supports the `%o` and `%O` specifiers for printing objects. [#14558](#14558) PR-URL: #14811

Notable changes * **HTTP2** * Experimental support for the built-in `http2` has been added via the `--expose-http2` flag. [#14239](#14239) * **Inspector** * `require()` is available in the inspector console now. [#8837](#8837) * Multiple contexts, as created by the `vm` module, are supported now. [#14465](#14465) * **N-API** * New APIs for creating number values have been introduced. [#14573](#14573) * **Stream** * For `Duplex` streams, the high water mark option can now be set independently for the readable and the writable side. [#14636](#14636) * **Util** * `util.format` now supports the `%o` and `%O` specifiers for printing objects. [#14558](#14558) PR-URL: #14811

Notable changes * **HTTP2** * Experimental support for the built-in `http2` has been added via the `--expose-http2` flag. [#14239](nodejs/node#14239) * **Inspector** * `require()` is available in the inspector console now. [#8837](nodejs/node#8837) * Multiple contexts, as created by the `vm` module, are supported now. [#14465](nodejs/node#14465) * **N-API** * New APIs for creating number values have been introduced. [#14573](nodejs/node#14573) * **Stream** * For `Duplex` streams, the high water mark option can now be set independently for the readable and the writable side. [#14636](nodejs/node#14636) * **Util** * `util.format` now supports the `%o` and `%O` specifiers for printing objects. [#14558](nodejs/node#14558) PR-URL: nodejs/node#14811

- Add separate APIs for creating different kinds of numbers, because creating a V8 number value from an integer is faster than creating one from a double. - When getting number values, avoid getting the current context because the context will not actually be used and is expensive to obtain. - When creating values, don't use v8::TryCatch (NAPI_PREAMBLE), because these functions have no possibility of executing JS code. Refs: nodejs#14379 PR-URL: nodejs#14573 Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

- Add separate APIs for creating different kinds of numbers, because creating a V8 number value from an integer is faster than creating one from a double. - When getting number values, avoid getting the current context because the context will not actually be used and is expensive to obtain. - When creating values, don't use v8::TryCatch (NAPI_PREAMBLE), because these functions have no possibility of executing JS code. Refs: #14379 Backport-PR-URL: #19447 PR-URL: #14573 Reviewed-By: Timothy Gu <timothygu99@gmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

jasongin requested review from addaleax, TimothyGu and mhdawson August 1, 2017 20:05

nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. node-api Issues and PRs related to the Node-API. labels Aug 1, 2017

jasongin added the performance Issues and PRs related to the performance of Node.js. label Aug 1, 2017

jasongin mentioned this pull request Aug 1, 2017

List of potential N-API breaking changes nodejs/abi-stable-node#271

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addaleax reviewed Aug 1, 2017

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cjihrig reviewed Aug 3, 2017

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mhdawson reviewed Aug 3, 2017

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addaleax approved these changes Aug 3, 2017

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cjihrig approved these changes Aug 4, 2017

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TimothyGu approved these changes Aug 4, 2017

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jasongin closed this Aug 8, 2017

jasongin force-pushed the napi-number-perf branch from bfb88a3 to af70c3b Compare August 8, 2017 00:34

jasongin deleted the napi-number-perf branch August 8, 2017 00:34

addaleax added the semver-minor PRs that contain new features and should be released in the next minor version. label Aug 13, 2017

addaleax mentioned this pull request Aug 13, 2017

v8.4.0 proposal #14811

Merged

MylesBorins added the dont-land-on-v6.x label Jan 11, 2018

MylesBorins mentioned this pull request Apr 16, 2018

v6.14.2 proposal #19996

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n-api: optimize number API performance #14573

n-api: optimize number API performance #14573

jasongin commented Aug 1, 2017

addaleax Aug 1, 2017

addaleax Aug 1, 2017

jasongin Aug 2, 2017

cjihrig Aug 3, 2017

jasongin Aug 3, 2017

mhdawson commented Aug 3, 2017

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jasongin commented Aug 3, 2017

TimothyGu Aug 4, 2017

jasongin Aug 7, 2017

jasongin commented Aug 7, 2017 •

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jasongin commented Aug 8, 2017

n-api: optimize number API performance #14573

n-api: optimize number API performance #14573

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jasongin commented Aug 1, 2017

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Affected core subsystem(s)

addaleax Aug 1, 2017

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jasongin Aug 2, 2017

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mhdawson commented Aug 3, 2017

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