Using node profiler util programs

node-profiler.md

#Introduction

So you have a program that is doing bad things and have isolated that to a test case, this guides you though using one of the tools bundled with node-profiler to read the v8 logs.

• Install node-profiler into your project directory.

npm install profiler --from-git git://github.com/wolfeidau/node-profiler.git#updated_v8_to_3.14.5.8

• Build the tools.

cd node_modules/profiler/tools
./build-nprof
cd -

• Run your test.

node --prof lev
node_modules/profiler/nprof

• Some sample output.

Statistical profiling result from v8.log, (67 ticks, 2 unaccounted, 0 excluded).

 [Unknown]:
   ticks  total  nonlib   name
      2    3.0%

 [Shared libraries]:
   ticks  total  nonlib   name
     51   76.1%    0.0%  /usr/local/bin/node
      8   11.9%    0.0%  /usr/lib/system/libsystem_c.dylib
      4    6.0%    0.0%  /usr/lib/system/libsystem_kernel.dylib

 [JavaScript]:
   ticks  total  nonlib   name
      1    1.5%   25.0%  LazyCompile: ~fs.closeSync fs.js:396
      1    1.5%   25.0%  LazyCompile: ~exec native regexp.js:168
      1    1.5%   25.0%  LazyCompile: ~defineProperties native v8natives.js:1102
      1    1.5%   25.0%  LazyCompile: ~Module._resolveFilename module.js:323

 [C++]:
   ticks  total  nonlib   name

 [GC]:
   ticks  total  nonlib   name
      2    3.0%

 [Bottom up (heavy) profile]:
  Note: percentage shows a share of a particular caller in the total
  amount of its parent calls.
  Callers occupying less than 2.0% are not shown.