Re: rtc max frequency setting

From: Jan Engelhardt
Date: Sun Aug 05 2007 - 04:06:11 EST



On Aug 4 2007 17:06, H. Peter Anvin wrote:
>Jan Engelhardt wrote:
>> Hi,
>>
>> with the old rtc.ko module, there was a /proc/sys/dev/rtc/max-user-freq
>> that could be set. With rtc_cmos.ko (or the new rtc infrastructure in
>> general), I am missing this file. Where can I set the max-user-freq now,
>> or is this obsolete now? (mplayer prefers to have user-freq to be >= 1024.)
>
>Qemu wants something like this too. Both of these really want something
>else, which is a high-frequency userspace timer.

Something like that. They use it to fire the virtual timer (RTC in
the guest), otherwise there is no way to simulate a HZ=1000 guest
(esp. Freebsd 6.0) in a HZ=100 host without busy-waiting.

For mplayer it is not that important (I'd even ask "what for?" since
other players do not need it either by default).

>What is the best way to do that on modern kernels?
>
> -hpa
>

Jan
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