# Spped step warning.

## GreazyMF

All,

If I type $ dmesg, I see some output which includes the following lines:

```

Using anticipatory io scheduler

Warning: Processor Platform Limit event detected, but not handled.

Consider compiling CPUfreq support into your kernel.

Losing too many ticks!

TSC cannot be used as a timesource.

Possible reasons for this are:

  You're running with Speedstep,

  You don't have DMA enabled for your hard disk (see hdparm),

  Incorrect TSC synchronization on an SMP system (see dmesg).

Falling back to a sane timesource now.

```

I am running kernel 2.6.9-gentoo-r9 on a Dell Latitiude D800 laptop. I'm a newbie, does anyone have any insight into this?

Thanks,

--Greazy

----------

## fatboyjim

 *GreazyMF wrote:*   

> 
> 
> ```
> 
> Consider compiling CPUfreq support into your kernel.
> ...

 

```

emerge cpufreq
```

 ?

Jim

----------

## toralf

 *Quote:*   

> 
> 
> Loosing too many ticks
> 
> 

 

 means that the precision timer actually used by the kernel is not good enough. You should have a look into the help text of the appropriate kernel option (it was one of the followings but I don't remember which option it was exactly):

```

nhh221 /usr/src/linux # grep -e TSC -e RTC -e HPET .config

# CONFIG_M586TSC is not set

CONFIG_HPET_TIMER=y

CONFIG_X86_TSC=y

CONFIG_RTC=m

# CONFIG_GEN_RTC is not set

CONFIG_HPET=y

# CONFIG_HPET_RTC_IRQ is not set

CONFIG_HPET_MMAP=y

# CONFIG_SENSORS_RTC8564 is not set

# CONFIG_SND_RTCTIMER is not set

```

Before you should compile cpufreq into your kernel (has nothing to do with "emerge cpufreq") and use "ondemand" as the default governour, works great. Than you do not need any userspace program.

----------

## fatboyjim

Although he will need to emerge CPUFreq if he wants to control the CPU stepping, correct?

Jim

----------

## toralf

 *fatboyjim wrote:*   

> Although he will need to emerge CPUFreq if he wants to control the CPU stepping, correct?
> 
> 

 

Not really. It is also possible to use commands like

```

echo ondemand  > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

```

or 

```

echo powersave  > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

```

from the command line (as root or with sudo as a normal user) or to use speedfreqd (which is easier to configure then cpufreqd as I read in this forum)

----------

## fatboyjim

Nice one, thanks for that

----------

