Added a new struct CallbackBundle to eliminate all
GetInternalField() calls.
The principle is to store all required data inside a C++ struct,
and then store the pointer in the JavaScript object. Before this
change, the required data are stored in the JavaScript object in
3 or 4 seperate pointers. For every napi fun call, 3 of them
have to be fetched out, which are 3 GetInternalField() calls;
after this change, the C++ struct will be directly fetched out
by using v8::External::Value(), which is faster.
Profiling data show that GetInternalField() is slow.
On an i7-4770K (3.50GHz) box, a C++ V8-binding fun call is 8 ns,
before this change, napi fun call is 36 ns; after this change,
napi fun call is 20 ns.
The above data are measured using a modified benchmark in
'benchmark/misc/function_call'. The modification adds an indicator
of the average time of a "chatty" napi fun call (max 50M runs).
This change will speed up chatty case 1.8x (overall), and will cut
down the delay of napi mechanism to approx. 0.5x.
Background: a simple C++ binding function (e.g. receiving little
from JS, doing little and returning little to JS) is called
'chatty' case for JS<-->C++ fun call routine.
This improvement also applies to getter/setter fun calls.
Backport-PR-URL: https://github.com/nodejs/node/pull/21733
PR-URL: https://github.com/nodejs/node/pull/21072
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>
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