Re: [Xen-devel] Re: [Xen-users] About profiling xen

To:	Pasi Kärkkäinen <pasik@xxxxxx>
Subject:	Re: [Xen-devel] Re: [Xen-users] About profiling xen
From:	Marco Tizzoni <marco.tizzoni@xxxxxxxxx>
Date:	Wed, 30 Sep 2009 11:06:25 +0200
Cc:	"Fajar A." <fajar@xxxxxxxxx>, Fasiha Ashraf <feehapk@xxxxxxxxxxx>, xen <xen-devel@xxxxxxxxxxxxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
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Enabling debug on kernel I realized the problem is related to timer accuracy.
------------------------------------------------------------------------
hal9k-dom0 ~ # cat /proc/timer_list
Timer List Version: v0.3
HRTIMER_MAX_CLOCK_BASES: 2
now at 784689453083 nsecs

cpu: 0
 clock 0:
 .index:      0
 .resolution: 999848 nsecs
[........]
hal9k-dom0 ~ # cat
/sys/devices/system/clocksource/clocksource0/available_clocksource
xen jiffies
hal9k-dom0 ~ # cat
/sys/devices/system/clocksource/clocksource0/current_clocksource
xen
------------------------------------------------------------------------

Is there a way to make available a better timer (hpet,acpi....)?

Also, on another xen box (rhel 5.2), I've a 'pit' clocksource in
available_clocksource.
After:
# sysctl -w xen.independent_wallclock=1

and
------------------------------------------------------------------------------------------------------------------------------------
# echo pit > /sys/devices/system/clocksource/clocksource0/current_clocksource
[root@station1 init.d]# cat
/sys/devices/system/clocksource/clocksource0/current_clocksource
jiffies
------------------------------------------------------------------------------------------------------------------------------------

the clocksource is unmodified.

m-

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Re: [Xen-devel] Re: [Xen-users] About profiling xen