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View Full Version : SCP copy over WiFi heavily decrease USB operations




l..k
Aug 5, 2012, 11:04 AM
Hello,

I have just posted about the problem on discussion.apple.com but it seems there is very few people knowing the internals of the OSX.

https://discussions.apple.com/message/19170155#19170155

EDIT: found the root cause of the problem - dying battery in my wireless keyboard. Why it degraded in operation under such condition, with SCP running, and not otherwise is a great mystery but a few days later it started to degrade all the time.

Hello,

As the title says, my Mac becomes very unresponsive when I copy large file via scp command. Keboard seems to read only a few letters than it "sleeps" acceptin a letter every ~2s, mouse moves "by hops" over the screen.

The scp seems to use available bandwith (~300kB/s), so seems ok. The CPU is 95% idle, so again seems OK. Disk is mostly idle.

My system configuration:
- Mac mini 5,1
- Lion
- USB keyboard + mouse (combo)

What else can I check to solve the problem? I need to use ssh/scp.

Update: Just when writing the post I got an idea to test Bluetooth keyboar+mouse. The result is that Bluetooth imput devices works without degradation, whilst at the same time the USB devices gets slow. I have tested the pendrive read/write and it is also affected by the SCP command. Any ideas why SCP over WiFi degrade USB operations? Is there any USB monitoring tool/command?

I do not want to stick with the crappy standard Bluetooth keyboard when I have a split ergonomic USB keyboard. Anyway, I was looking for a good ergonimic Bluetooth keyboard but was unsuccessful. However the exclusive, either scp either USB at a time, copy operation is also a hindrance.

Thanks in advance!



ScoobyMcDoo
Aug 5, 2012, 03:59 PM
Is the drive you are copying to/from a USB drive?

Use system profiler to see how things are hooked up on your USB busses. You might be able to improve things by simply plugging your keyboard/mouse into a different usb port.

l..k
Aug 6, 2012, 12:45 AM
Is the drive you are copying to/from a USB drive?


No, I copied from my internal drive. What profile tools do you think about? Is there something more advanced than the ActivityMonitor?

stchman
Aug 6, 2012, 05:09 PM
When I first got my MBA I had to transfer ~30GB of files from my Ubuntu Dell laptop. I had no problems whatsoever with system responsiveness using the scp command.

It would be VERY nice if Finder had SSH/SFTP built-in like Nautilus

ScoobyMcDoo
Aug 6, 2012, 06:53 PM
When I first got my MBA I had to transfer ~30GB of files from my Ubuntu Dell laptop. I had no problems whatsoever with system responsiveness using the scp command.

It would be VERY nice if Finder had SSH/SFTP built-in like Nautilus

It would be nice, but Cyberduck and Filezilla are both nice editions which give this capability

----------

No, I copied from my internal drive. What profile tools do you think about? Is there something more advanced than the ActivityMonitor?

Click on the :apple:->about this mac->more info->system report. Then on the left column click on USB. From there you can see the topology of your USB connections.

I have never had a mini. I have never had a problem with my mbp or imac when using scp.

l..k
Aug 7, 2012, 02:54 AM
Click on the :apple:->about this mac->more info->system report. Then on the left column click on USB. From there you can see the topology of your USB connections.

I have never had a mini. I have never had a problem with my mbp or imac when using scp.

Thanks, but the USB topology does not reveal anything interesting. The problem happens with keyboard only attached. Sure, there are other devices on the buss which are internal to the mini, but again how can I tell if they cause problems?

I am thinking of installing Debian natively, and OSX as virtual machine. The OS X is quite interesting, have neat visual style, good set of applications, but the performance is far behind Linux or MS Windows.

Sure, I hope the performance could be tuned. Unfortunately there is really very scarce know-how amongst mac users. Mac users seems to love their mac and get things "as is". There is no much difference amongst MS Windows users either but MS seems to care more about their OS and spend much bigger budget to test it thoroughly, document things and sustain. OS X seems close to Linux so I was hoping the same level of community knowledge would be available as for Linux :(

I found a book http://osxbook.com
which seems to explain the system a little.
http://osxbook.com/images/cover.jpg

Does anyone know any better book/resource?

"Why do I have to learn internals of all things I bought to make them work as they supposed to in the first place??" :confused: