PSA: Disable App Nap in Launcher.app for sustained download speed in 10.9

KhajitFurTrader

So it turns out that every time the Launcher.app window loses focus, the download speed gets very erratic. It falls down to a bare minimum, only to shoot up to maximum for a short while, then falls again. I left the Launcher open overnight to get the PTS client, and it still hasn't arrived completely.

This behavior can be attributed to the OS X Mavericks App Nap feature. My guess is that there are system calls that will prevent an application from being throttled while in the background, but the Launcher doesn't use them (yet).

In order to disable App Nap for the Launcher, follow these steps:

• Open a Finder window and navigate to /Applications/ZeniMax Online
• [Right-click] on Launcher.app, then [Click] on "Get Info"
• In the Info window under the "General" section, check the box "Prevent App Nap"
• Close the Info window

Chances are these steps will have to be repeated every time there's an update to the Launcher itself.

PrinceBoru

Awesome tip!
I noticed this myself.
The Launcher losing focus choked off the download speed.
Thank you!

Moonraker

Interesting. I do know that generally I don't have the option ticked (Disabled) and it downloads full bandwidth most of the time. Occasionally slows down which I put down to network or server.

I wonder if there is a difference when using a wired connection to the router (ethernet as I do) and wireless.

I noted back in beta phase that when the Launcher is launched the Display wont sleep even when set in System Preferences > Energy Saver. You can see this if you set it to 1 minute with Launcher not launched and it should sleep as anticipated after around 1 minute (other apps may prevent it also). Launch Launcher and it never sleeps. I felt that it was a potential issue with anyone using CRT monitors due to burn-in etc. And although LED displays don't have the same issue there are reports of other issues with displays left on with static windows over time.

Anyhow, it appears to keep producing wakeup calls in order to ensure it is not slept for downloads. This does produce continual reports in DiagnosticReports on the Mac like this

ZeniMax Online Studios Launcher_2014-08-19-235914_xxxxx.wakeups_resource.spin

Which includes just how high these calls are;

Command: ZeniMax Online Studios Launcher
Path: /Applications/ZeniMax Online/Launcher.app/Contents/MacOS/ZeniMax Online Studios Launcher
Version: 3.5.2 (3.5.2.0)
Parent: launchd [158]

PID: 1615
Event: wakeups (microstackshots only)
Wakeups: 399 wakeups per second for 113 seconds
Duration: 113.00s
Steps: 113

It is not the only process that generates these wakeups which are part of the OS X energy management and App Nap but it should not be producing so many is correctly optimised according to Apple;

App Nap - Debugging
There are many new tools available on the system to investigate the root cause of unexpected battery drain. Xcode now includes a view of the energy usage when running your application. Activity Monitor includes a new column that shows if your app is in App Nap or not, plus a synthesized “power score” which indicates the overall power usage of your app. The battery menu extra will now report apps using an excessive amount of power. The new command line tool timerfires (“man timerfires” for more information) can be used to investigate what timers your application has scheduled.

You should strive to have a power score of 0.0 and 0 idle wake ups. Remember that even a small amount of CPU usage can have a significant effect on battery life.

You can see this easily by launching Launcher then opening Activity Monitor > CPU and the Idle Wake Ups column and ZeniMax Online Studios Launcher (Launcher) will often be at the top generating around 300-400 per second. A lot more than most other processes.

I don't think it's inherently bad but probably not correctly optimised/ handled by Launcher. Maybe just their way to stop the computer sleeping even though it does it when downloading or not.

Related to this check the Activity Monitor > Energy section and see just how much energy the process is using even just left idle in the background (for me it shows around 19.0 which is way higher than other normal processes all lower or around 1.0) For laptops if the power cable not plugged in it will be eating up the battery just left in the background with the game playing. Another reason to quit it once the game is launched.

It is one consideration if you disable App Naps and generally when Launcher is active.

PrinceBoru

So I went to look for the checkbox.
D'oh!
My Mac must not support it.
Back to keeping the Launcher on top.

PrinceBoru

...this just in...
when I hide the Launcher during a repair it slows waaaay down too!