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Accepted
Andrew Clegg
Asked: 2012-06-16 01:28:25 +0800 CST

LatencyTop on Centos 6.2

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What do I need to do to get LatencyTop working on Centos 6.2?

Does it involve compiling a debug kernel with some extra flags?

Both the man page and the website are very short of information.

Thanks!

EDIT: I should have been more specific, sorry, my bad. I've installed it fine from an rpm. But apparently the stock Centos 6.2 kernel doesn't support it:

mount: none already mounted or /sys/kernel/debug/ busy
mount: according to mtab, none is already mounted on /sys/kernel/debug
Xlib:  extension "RANDR" missing on display "localhost:10.0".
The running kernel does not support latencytop. Please use kernel-debug.

No idea how to install and use kernel-debug safely though, if this is the only extra thing that needs to be done. Does anyone have any pointers?

Thanks again.

performance linux centos latency

2 Answers

  1. It's included in the RPMForge repository, so you just have to include this repo in your system and then install it with yum install latencytop.

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  2. Best Answer

    LatencyTOP requires you to rebuild the kernel and enable the CONFIG_LATENCYTOP parameter if you wish to use a standard kernel version. Yes, the package downloads and installs, but the flag is not enabled by default, hence the error message you see.

    Your other option is to heed the error message and install the kernel-debug package. Reboot with the new kernel set as the boot kernel (either choose manually in the grub menu or edit grub.conf).

    The note about debugfs is a red herring. Pay attention to: "The running kernel does not support latencytop. Please use kernel-debug."

    The next issue is that LatencyTop is an X11 application. Hopefully you have those libraries installed. I enable X11 forwarding through ssh (ssh -X hostname) and am able to view the LatencyTOP window remotely.

    enter image description here

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