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Update guide: "Easy profiling for Node.js" #449

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Update guide: "Easy profiling for Node.js" #449

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15 changes: 5 additions & 10 deletions locale/en/docs/guides/simple-profiling.md
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Expand Up @@ -21,7 +21,7 @@ code-creation,Stub,2,0x2d5000a33e00,507,"NumberToStringStub"
```

In the past you need the V8 source code to be able to interpret the ticks.
Luckily, tools have recently been introduced into Node.js 4.1.1 that facilitate
Luckily, tools have recently been introduced into Node.js 5.2.0 that facilitate
the consumption of this information without separately building V8 from source.
Let's see how the built-in profiler can help provide insight into application
performance.
Expand Down Expand Up @@ -134,15 +134,11 @@ passwords, or inside the Express framework itself.
Since we ran our application using the --prof option, a tick file was generated
in the same directory as your local run of the application. It should have the
form isolate-0x124353456789-v8.log. In order to make sense of this file, we need
to use the tick processor included in the Node.js source at
<nodejs_dir>/tools/v8-prof/tick-processor.js. It is important that the version
of the tick-processor that you run comes from the same version of node source as
version of node used to generate the isolate file. This will no longer be a
concern when the tick processor is [installed by default][]. The raw tick output
can be processed using this tool by running:
to use the tick processor which is bundled inside the Node.js binary. The raw tick
output can be processed using this tool by running:

```
node <path_to_nodejs_src>/tools/v8-prof/tick-processor.js isolate-0x101804c00-v8.log >processed.txt
node --prof-process isolate-0x101804c00-v8.log >processed.txt
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Nit: We probably want to find some way to generalize the file name. I wouldn't hold this up for that, though, if that is likely to be the source of much bike-shedding.

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Can we please keep the old command as well for users of 4.2 (LTS)?

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Based on the discussion here, it seems likely that this change will land in LTS. My hope is to update the guide at that time to move the required version back from 5.2.0 to 4.2.x.

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@Trott I thought the way you handled this generalization in #446 was good. I would be happy waiting for that one to land and then merging this change on top.

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If someone wants to merge #446, great! If you'd rather just add that change into here yourself, that's great too!

```

Opening processed.txt in your favorite text editor will give you a few different
Expand Down Expand Up @@ -174,7 +170,7 @@ taking the most CPU time and see:
```

We see that the top 3 entries account for 72.1% of CPU time taken by the
program.From this output, we immediately see that at least 51.8% of CPU time is
program. From this output, we immediately see that at least 51.8% of CPU time is
taken up by a function called PBKDF2 which corresponds to our hash generation
from a user's password. However, it may not be immediately obvious how the lower
two entries factor into our application (or if it is we will pretend otherwise
Expand Down Expand Up @@ -282,5 +278,4 @@ example, you've seen how the V8 tick processor can help you gain a better
understanding of the performance of your Node.js applications.

[profiler inside V8]: https://developers.google.com/v8/profiler_example
[installed by default]: https://github.com/nodejs/node/pull/3032
[benefits of asynchronous programming]: https://nodesource.com/blog/why-asynchronous