[Qemu-devel] /dev/rtc issues

[Qemu-devel] /dev/rtc issues

[Lorenzo Campedelli]

Like others have reported to the list I'm getting:

Could not configure '/dev/rtc' to have a 1024 Hz timer. This is not a fatal
error, but for better emulation accuracy either use a 2.6 host Linux 
kernel or
type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as root.

and then

[root@arturo ~]# echo 1024 > /proc/sys/dev/rtc/max-user-freq
-bash: /proc/sys/dev/rtc/max-user-freq: No such file or directory

[root@arturo ~]# uname -a
Linux arturo 2.6.22.1-32.fc6 #1 SMP Wed Aug 1 15:15:33 EDT 2007 i686 
i686 i386 GNU/Linux


I guess this is due to changes in the latest host kernel, in particular 
to Dyntick, introduced in 2.6.21 (see http://lwn.net/Articles/223185/).

Does anybody know whether/how this affects qemu and kqemu operation?

Thanks in advance,
Lorenzo

RE: [Qemu-devel] /dev/rtc issues

[Dor Laor]

>Like others have reported to the list I'm getting:
>
>Could not configure '/dev/rtc' to have a 1024 Hz timer. This is not a
>fatal
>error, but for better emulation accuracy either use a 2.6 host Linux
>kernel or
>type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as root.

It's might be HPET that bothers rtc.
You can apply Luca's HPET support for qemu patch.
http://article.gmane.org/gmane.comp.emulators.kvm.devel/5639



>
>and then
>
>[root@arturo ~]# echo 1024 > /proc/sys/dev/rtc/max-user-freq
>-bash: /proc/sys/dev/rtc/max-user-freq: No such file or directory
>
>[root@arturo ~]# uname -a
>Linux arturo 2.6.22.1-32.fc6 #1 SMP Wed Aug 1 15:15:33 EDT 2007 i686
>i686 i386 GNU/Linux
>
>
>I guess this is due to changes in the latest host kernel, in particular
>to Dyntick, introduced in 2.6.21 (see http://lwn.net/Articles/223185/).
>
>Does anybody know whether/how this affects qemu and kqemu operation?
>
>Thanks in advance,
>Lorenzo
>
>