LatencyTop problem

LatencyTop problem

[Mauro Andreolini]

Hi everyone,

I tried to get latencytop (Debian testing package, v.0.4) running on a
2.6.27 vanilla kernel. When I try to execute latencytop as root, I get
the following message:

Error writing to /proc/sys/kernel/latencytop: No such file or directory
Error writing to /proc/sys/kernel/latencytop: No such file or directory
Are you root?
Please enable the CONFIG_LATENCYTOP configuration in your kernel.
Exiting...

I am pretty sure that the CONFIG_LATENCYTOP is set in the kernel.
I tried to download and apply the latencytop patch, but it rejects some
hunks. It seems as if the executable wants to
open /proc/sys/kernel/latencytop for writing but it can't, because the
piece of kernel code that enables it (kernel/latencytop.c) does not
create that /proc file. The code to enable /proc/sys/kernel/latencytop
is contained in the kernel patch from the project home page, anyway.
Instead, reading the code in the 2.6.27 kernel, a "latency_stats" file
should be created, but that is not present under both the /proc and /sys
filesystems.
Could anyone of you point me to a procedure to get latencytop working
with a recent kernel?
Thank you in advance.

Mauro Andreolini

Re: LatencyTop problem

[Arjan van de Ven]

On Sat, 18 Oct 2008 18:49:18 +0200
Mauro Andreolini <mauro.andreolini@unimore.it> wrote:

> Hi everyone,
> 
> I tried to get latencytop (Debian testing package, v.0.4) running on a
> 2.6.27 vanilla kernel. When I try to execute latencytop as root, I get
> the following message:
> 
> Error writing to /proc/sys/kernel/latencytop: No such file or
> directory Error writing to /proc/sys/kernel/latencytop: No such file
> or directory Are you root?
> Please enable the CONFIG_LATENCYTOP configuration in your kernel.
> Exiting...
> 
> I am pretty sure that the CONFIG_LATENCYTOP is set in the kernel.

I just tried, and the file exists just fine for me... I think there's
something weird going on with your kernel, like you might not be
running the kernel you thought you were running...

-- 
Arjan van de Ven 	Intel Open Source Technology Centre
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org

Re: LatencyTop problem

[Mauro Andreolini]

> I just tried, and the file exists just fine for me... I think there's
> something weird going on with your kernel, like you might not be
> running the kernel you thought you were running...
You were right, it was a silly mistake by me. Latencytop works just great.
Sorry for the noise and thanks for your prompt response.

Mauro Andreolini