Kazu wrote:

>If you set /proc/sys/dev/rtc/max-user-freq to 1024 and disable cpuspeed
>service that is related to SpeedStep/PowerNow! on a host OS, the clock in
>guest OS works fine.
>
>I checked it on i686/x86_64 Linux host.
>
   Mind saying how you checked this?  I'm on a pentium-III mobile 
processor and the only way I've seen so far to make qemu + rdtsc behave 
100% is by disabling ACPI (boot with -noacpi).  If I add a simple printf 
to cpu_calibrate_ticks it doesn't seem fixed to me:

dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 1126809000
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 17308857
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 103710852
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 15292604
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 96695295
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 1126761234
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 1126762522
dignome@vaio /prog/qemu-stuff $ qemu -localtime -hda winxp.img -no-acpi 
-kernel-kqemu -soundhw es1370
ticks_per_sec set as 49791263

   The first entry is with the patch attached called 
'ticks_from_proc.patch' applied (I've been using this for almost a 
year).  It sets the value ticks_per_sec, which happens to be used by a 
lot of qemu's hardware emulation, using information in /proc/cpuinfo.  
This doesn't fix the time issue as rdtsc is still used every time a 
SIGALRM signal occurs for timing, but at least the guest's emulated 
hardware runs to speed.

dignome@vaio /prog/qemu-cvs/qemu-acpi/qemu $ find . -type f -exec fgrep 
-l 'ticks_per_sec' {} \;
./audio/audio.c
./audio/noaudio.c
./audio/wavaudio.c
./monitor.c
./vl.c
./vl.h
./hw/acpi.c
./hw/adlib.c
./hw/arm_timer.c
./hw/cuda.c
./hw/fdc.c
./hw/i8254.c
./hw/i8259.c
./hw/ide.c
./hw/mc146818rtc.c
./hw/mips_r4k.c
./hw/ppc.c
./hw/sb16.c
./hw/sh7750.c
./hw/slavio_timer.c
./hw/usb-uhci.c

   The second patch adds the printf statement so you can see this for 
yourself.