mmarchini

V8 Heap Snapshot Schema

Key	Description
snapshot	Metadata from the snapshot. See snapshot
nodes	List of heap nodes. See nodes
edges	List of heap edges between nodes. See edges
trace_function_infos	???
trace_tree	???

mmarchini

Chrome DevTools Heap Snapshot Loading Benchmark

Benchmark of the Chrome DevTools to determine if it can load large Heap Snapshots. Specs of the environment used are available at Environment Specs.

Results

Time to Load is an approximate value, as there's no way (that I'm aware of) to measure the loading time of a heap snapshot in Chrome DevTools.

mmarchini

Node v6.x runtime --perf-basic-prof toggling

Builds

Linux x86: node-v6.12.3

Linux x64: node-v6.12.3

Docker apline image: docker pull sthima/node-custom-build:toggle-perf-basic-prof (Dockerfile)

mmarchini

v8-version,6,1,534,48,0
shared-library,"/usr/bin/node",0x00400000,0x01fa2000,0
shared-library,"/lib/x86_64-linux-gnu/libc-2.26.so",0x7f8a84f0c000,0x7f8a850e2000,0
shared-library,"/lib/x86_64-linux-gnu/libpthread-2.26.so",0x7f8a852ec000,0x7f8a85306000,0
shared-library,"/lib/x86_64-linux-gnu/libgcc_s.so.1",0x7f8a8550b000,0x7f8a85521000,0
shared-library,"/lib/x86_64-linux-gnu/libm-2.26.so",0x7f8a85722000,0x7f8a85877000,0
shared-library,"/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.24",0x7f8a85a78000,0x7f8a85bf0000,0
shared-library,"/lib/x86_64-linux-gnu/librt-2.26.so",0x7f8a85dfe000,0x7f8a85e05000,0
shared-library,"/lib/x86_64-linux-gnu/libdl-2.26.so",0x7f8a86006000,0x7f8a86009000,0
shared-library,"/lib/x86_64-linux-gnu/ld-2.26.so",0x7f8a8620a000,0x7f8a86231000,0

mmarchini

$ node benchmark/compare.js --old ./node-master --new ./node-hack-the-stack http > compare-hack-the-stack.http.csv
$ cat compare-hack-the-stack.http.csv  | Rscript benchmark/compare.R
                                                                                                confidence improvement accuracy (*)    (**)   (***)
 http/bench-parser.js n=100000 len=16                                                                          -1.17 %       ±3.73%  ±4.96%  ±6.46%
 http/bench-parser.js n=100000 len=32                                                                          -1.55 %       ±3.19%  ±4.24%  ±5.52%
 http/bench-parser.js n=100000 len=4                                                                           -2.90 %       ±4.20%  ±5.59%  ±7.27%
 http/bench-parser.js n=100000 len=8                                                                           -2.39 %       ±3.41%  ±4.54%  ±5.91%
 http/check_invalid_header_char.js n=1000000 input=''                                       

mmarchini

#!/usr/bin/env zsh

local LAMBDA="%(?,%{$fg_bold[green]%}λ,%{$fg_bold[red]%}λ)"

function get_pwd(){
  git_root=$PWD
  while [[ $git_root != / && ! -e $git_root/.git ]]; do
    git_root=$git_root:h
  done
  if [[ $git_root = / ]]; then

mmarchini

'use strict';

const http = require('http');
const port = 3000;

class Visit {
  constructor(visit_id, headers) {
    this.visit_id = visit_id;
    this.headers = headers;
  }

mmarchini

#include <v8.h>
#include <v8-postmortem.h>
#include <napi.h>
#include <lldb/API/SBDebugger.h>
#include <lldb/API/SBTarget.h>
#include <lldb/API/SBProcess.h>

#include <iostream>

using lldb::addr_t;

mmarchini

Goals

When a promise is rejected with no catch handler attached, it should:

• Aborting with error code for unhandled rejection to generate core-dump
• Get stack trace from the point where the error was thrown
• Inspecting arguments, closures and variables

Current State

mmarchini

(lldb) target create "/home/mmarchini/.nvm/versions/node/v12.3.0/bin/node" --core "core.frame-scenario.1"
Core file '/home/mmarchini/workspace/nodejs/llnode/core.frame-scenario.1' (x86_64) was loaded.
(lldb) plugin load '/home/mmarchini/workspace/nodejs/llnode/llnode.so'
(lldb) settings set prompt '(llnode) '
(llnode) command script import diagnose_unwind
bind: Invalid command `enable-meta-key'.
The "diagnose-unwind" command has been installed, type "help diagnose-unwind" for detailed help.
(llnode) diagnose-unwind
LLDB version lldb version 6.0.1
Unwind diagnostics for thread 1