Is sysfs expected to work fully in an hvm guest?
In RHEL5 (2.6.18-based) kernels, the following works native
/sys/devices/system/clocksource/clocksource0/...
available_clocksource lists the possible clock sources
current_clocksource lists the chosen clock source,
and can be changed on the fly
but don't work for me from within an RHEL5 HVM guest.
All reads yield only "jiffies" (which I believe is the
default setting) even though there are other clock
sources available and set, and echo'ing to the
current_clocksource doesn't seem to change it.
Should I expect that it would work? If so, does it work
on your system? Perhaps it is something peculiar to
my environment?
Thanks,
Dan
==================================If Xen could save time in a bottle / then
clocks wouldn't virtually skew /
It would save every tick / for VMs that aren't quick /
and Xen then would send them anew
(with apologies to the late great Jim Croce)
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Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel
Hmmm... this seems to work fine when booting a 32-bit RHEL5 on 32-bit dom0 on 32-bit xen and with 32-on-32-on-64, but fails with 64-bit RHEL5 on 32-bit dom0 on 64-bit xen. Not sure yet if this is a problem with the specific guest instance or what.> -----Original Message----- > From: xen-devel-bounces@lists.xensource.com > [mailto:xen-devel-bounces@lists.xensource.com]On Behalf Of Dan > Magenheimer > Sent: Tuesday, February 19, 2008 9:48 PM > To: xen-devel@lists.xensource.com > Subject: [Xen-devel] sysfs on hvm guests? > > > Is sysfs expected to work fully in an hvm guest? > > In RHEL5 (2.6.18-based) kernels, the following works native > > /sys/devices/system/clocksource/clocksource0/... > available_clocksource lists the possible clock sources > current_clocksource lists the chosen clock source, > and can be changed on the fly > > but don't work for me from within an RHEL5 HVM guest. > > All reads yield only "jiffies" (which I believe is the > default setting) even though there are other clock > sources available and set, and echo'ing to the > current_clocksource doesn't seem to change it. > > Should I expect that it would work? If so, does it work > on your system? Perhaps it is something peculiar to > my environment? > > Thanks, > Dan > > ==================================> If Xen could save time in a bottle / then clocks wouldn't > virtually skew / > It would save every tick / for VMs that aren't quick / > and Xen then would send them anew > (with apologies to the late great Jim Croce) >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Double hmmm... it seems that even on hardware 64-bit RHEL5 reports only jiffies for these sysfs clocksource variables even though other clocksources are available and current. Not sure if this is a bug or a feature, but its definitely not a Xen problem. Sorry for the false alarm. Dan> -----Original Message----- > From: Dan Magenheimer [mailto:dan.magenheimer@oracle.com] > Sent: Wednesday, February 20, 2008 8:06 AM > To: dan.magenheimer@oracle.com; xen-devel@lists.xensource.com > Subject: RE: [Xen-devel] sysfs on hvm guests? > > > Hmmm... this seems to work fine when booting a 32-bit RHEL5 on > 32-bit dom0 on 32-bit xen and with 32-on-32-on-64, but fails with > 64-bit RHEL5 on 32-bit dom0 on 64-bit xen. Not sure yet if > this is a problem with the specific guest instance or what. > > > -----Original Message----- > > From: xen-devel-bounces@lists.xensource.com > > [mailto:xen-devel-bounces@lists.xensource.com]On Behalf Of Dan > > Magenheimer > > Sent: Tuesday, February 19, 2008 9:48 PM > > To: xen-devel@lists.xensource.com > > Subject: [Xen-devel] sysfs on hvm guests? > > > > > > Is sysfs expected to work fully in an hvm guest? > > > > In RHEL5 (2.6.18-based) kernels, the following works native > > > > /sys/devices/system/clocksource/clocksource0/... > > available_clocksource lists the possible clock sources > > current_clocksource lists the chosen clock source, > > and can be changed on the fly > > > > but don't work for me from within an RHEL5 HVM guest. > > > > All reads yield only "jiffies" (which I believe is the > > default setting) even though there are other clock > > sources available and set, and echo'ing to the > > current_clocksource doesn't seem to change it. > > > > Should I expect that it would work? If so, does it work > > on your system? Perhaps it is something peculiar to > > my environment? > > > > Thanks, > > Dan > > > > ==================================> > If Xen could save time in a bottle / then clocks wouldn't > > virtually skew / > > It would save every tick / for VMs that aren't quick / > > and Xen then would send them anew > > (with apologies to the late great Jim Croce) > > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
If anybody cares, it appears this is a 64-bit kernel bug that has been fixed upstream post-2.6.18.> -----Original Message----- > From: Dan Magenheimer [mailto:dan.magenheimer@oracle.com] > Sent: Wednesday, February 20, 2008 8:36 AM > To: dan.magenheimer@oracle.com; xen-devel@lists.xensource.com > Subject: RE: [Xen-devel] sysfs on hvm guests? > > > Double hmmm... it seems that even on hardware 64-bit RHEL5 > reports only jiffies for these sysfs clocksource variables > even though other clocksources are available and current. > > Not sure if this is a bug or a feature, but its definitely > not a Xen problem. > > Sorry for the false alarm. > > Dan > > > -----Original Message----- > > From: Dan Magenheimer [mailto:dan.magenheimer@oracle.com] > > Sent: Wednesday, February 20, 2008 8:06 AM > > To: dan.magenheimer@oracle.com; xen-devel@lists.xensource.com > > Subject: RE: [Xen-devel] sysfs on hvm guests? > > > > > > Hmmm... this seems to work fine when booting a 32-bit RHEL5 on > > 32-bit dom0 on 32-bit xen and with 32-on-32-on-64, but fails with > > 64-bit RHEL5 on 32-bit dom0 on 64-bit xen. Not sure yet if > > this is a problem with the specific guest instance or what. > > > > > -----Original Message----- > > > From: xen-devel-bounces@lists.xensource.com > > > [mailto:xen-devel-bounces@lists.xensource.com]On Behalf Of Dan > > > Magenheimer > > > Sent: Tuesday, February 19, 2008 9:48 PM > > > To: xen-devel@lists.xensource.com > > > Subject: [Xen-devel] sysfs on hvm guests? > > > > > > > > > Is sysfs expected to work fully in an hvm guest? > > > > > > In RHEL5 (2.6.18-based) kernels, the following works native > > > > > > /sys/devices/system/clocksource/clocksource0/... > > > available_clocksource lists the possible clock sources > > > current_clocksource lists the chosen clock source, > > > and can be changed on the fly > > > > > > but don't work for me from within an RHEL5 HVM guest. > > > > > > All reads yield only "jiffies" (which I believe is the > > > default setting) even though there are other clock > > > sources available and set, and echo'ing to the > > > current_clocksource doesn't seem to change it. > > > > > > Should I expect that it would work? If so, does it work > > > on your system? Perhaps it is something peculiar to > > > my environment? > > > > > > Thanks, > > > Dan > > > > > > ==================================> > > If Xen could save time in a bottle / then clocks wouldn't > > > virtually skew / > > > It would save every tick / for VMs that aren't quick / > > > and Xen then would send them anew > > > (with apologies to the late great Jim Croce) > > > > > >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel