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nodejs/tools/generate_code_cache.js
Joyee Cheung 0858e5d9d8
src: always compile and store code cache for native modules
This patch changes the NativeModuleLoader to always try to find
code cache for native modules when it compiles them, and always
produce and store the code cache after compilation. The cache
map is protected by a mutex and can be accessed by different
threads - including the worker threads and the main thread. Hence any
thread can reuse the code cache if the native module has already
been compiled by another thread - in particular the cache of the
bootstrappers and per_context.js will always be hit when a new thread
is spun.

This results in a ~6% startup overhead in the worst case
(when only the main thread is launched without requiring any additional
native module - it now needs to do the extra work of finding and
storing caches), which balances out the recent improvements by moving
the compilation to C++, but it also leads to a ~60% improvement in
the best case (when a worker thread is spun and requires a lot of native
modules thus hitting the cache compiled by the main thread).

PR-URL: https://github.com/nodejs/node/pull/24950
Reviewed-By: Anna Henningsen <anna@addaleax.net>
2018-12-18 18:02:11 +08:00

128 lines
3.3 KiB
JavaScript

'use strict';
// Flags: --expose-internals
// This file generates the code cache for builtin modules and
// writes them into static char arrays of a C++ file that can be
// compiled into the binary using the `--code-cache-path` option
// of `configure`.
const {
getCodeCache,
compileFunction,
cachableBuiltins
} = require('internal/bootstrap/cache');
const {
types: {
isUint8Array
}
} = require('util');
const fs = require('fs');
const resultPath = process.argv[2];
if (!resultPath) {
console.error(`Usage: ${process.argv[0]} ${process.argv[1]}` +
'path/to/node_code_cache.cc');
process.exit(1);
}
/**
* Format a number of a size in bytes into human-readable strings
* @param {number} num
* @return {string}
*/
function formatSize(num) {
if (num < 1024) {
return `${(num).toFixed(2)}B`;
} else if (num < 1024 ** 2) {
return `${(num / 1024).toFixed(2)}KB`;
} else if (num < 1024 ** 3) {
return `${(num / (1024 ** 2)).toFixed(2)}MB`;
} else {
return `${(num / (1024 ** 3)).toFixed(2)}GB`;
}
}
/**
* Generates the source code of definitions of the char arrays
* that contains the code cache and the source code of the
* initializers of the code cache.
*
* @param {string} key ID of the builtin module
* @param {Uint8Array} cache Code cache of the builtin module
* @return { definition: string, initializer: string }
*/
function getInitalizer(key, cache) {
const defName = `${key.replace(/\//g, '_').replace(/-/g, '_')}_raw`;
const definition = `static const uint8_t ${defName}[] = {\n` +
`${cache.join(',')}\n};`;
const dataDef = 'std::make_unique<v8::ScriptCompiler::CachedData>(' +
`${defName}, static_cast<int>(arraysize(${defName})), ` +
'policy)';
const initializer =
'code_cache_.emplace(\n' +
` "${key}",\n` +
` ${dataDef}\n` +
');';
return {
definition, initializer
};
}
const cacheDefinitions = [];
const cacheInitializers = [];
let totalCacheSize = 0;
function lexical(a, b) {
if (a < b) {
return -1;
}
if (a > b) {
return 1;
}
return 0;
}
for (const key of cachableBuiltins.sort(lexical)) {
compileFunction(key); // compile it
const cachedData = getCodeCache(key);
if (!isUint8Array(cachedData)) {
console.error(`Failed to generate code cache for '${key}'`);
process.exit(1);
}
const size = cachedData.byteLength;
totalCacheSize += size;
const {
definition, initializer,
} = getInitalizer(key, cachedData);
cacheDefinitions.push(definition);
cacheInitializers.push(initializer);
console.log(`Generated cache for '${key}', size = ${formatSize(size)}` +
`, total = ${formatSize(totalCacheSize)}`);
}
const result = `#include "node_native_module.h"
#include "node_internals.h"
// This file is generated by tools/generate_code_cache.js
// and is used when configure is run with \`--code-cache-path\`
namespace node {
namespace native_module {
${cacheDefinitions.join('\n\n')}
void NativeModuleLoader::LoadCodeCache() {
auto policy = v8::ScriptCompiler::CachedData::BufferPolicy::BufferNotOwned;
${cacheInitializers.join('\n ')}
}
} // namespace native_module
} // namespace node
`;
fs.writeFileSync(resultPath, result);
console.log(`Generated code cache C++ file to ${resultPath}`);