Hi! I would like to know the status of the frequency scaling in XEN. I found a web site saying that XEN doesn’t work with frequency scaling, at the other hand I found some fixes for powernow-k8 to get rid of some messages. I have an AMD64. powerno-k8 works find with non-XEN kernels, but with XEN-kernels I get the error: powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3400+ processors (version 2.00.00) powernow-k8: BIOS error - no PSB or ACPI _PSS objects This is normally a BIOS error and a BIOS update can fix it, but it works for me with non-XEN kernels, so in my case it can’t be a BIOS problem. So any information is welcome. Thanks! Shade and sweet water! Stephan -- | Stephan Seitz E-Mail: Nur-Ab-Sal@gmx.de | | PGP Public Keys: http://fsing.rootsland.net/~stse/pgp.html | _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > Stephan Seitz > Sent: 28 April 2007 21:25 > To: xen-users > Subject: [Xen-users] Status of frequency scaling > > Hi! > > I would like to know the status of the frequency scaling in > XEN. I found > a web site saying that XEN doesn''t work with frequency > scaling, at the > other hand I found some fixes for powernow-k8 to get rid of some > messages.Well, the current official status is "it doesn''t work at all". There are several problems, some of which are relatively easy to fix and some that aren''t: 1. The white-list of MSR''s that can be written doesn''t include the FID/VID MSR''s. This is VERY easy to fix - a few lines of code added to traps.c in the function dealing with MSR read/write operations will take care of that. 2. There is no power-management policy for the entire system, so dom0 usage will determine the entire system''s performance. This doesn''t work very well, as Dom0 isn''t supposed to be heavily loaded, DomU''s are. 3. Guest may need to be informed of the frequency change. Some kernels may not appreciate that the CPU frequency is chaning "without it''s knowledge". [This is probably not a big problem on modern OS''s, but some older ones may be very un-co-operative on this account].> > I have an AMD64. powerno-k8 works find with non-XEN kernels, but with > XEN-kernels I get the error: > > powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3400+ > processors (version 2.00.00) > powernow-k8: BIOS error - no PSB or ACPI _PSS objectsThis is strange - as far as I can remember, I had powernow working on my machine not so long ago (3.0.4 or so) with only the traps.c patched to allow writing of the FID/VID controls registers. You''re doing this in Dom0 I take it? I don''t expect this to work in DomU''s. -- Mats _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Mon, Apr 30, 2007 at 11:47:03AM +0200, Petersson, Mats wrote:>Well, the current official status is "it doesn''t work at all".Hm, okay.>There are several problems, some of which are relatively easy to fix and >some that aren''t: >2. There is no power-management policy for the entire system, so dom0 >usage will determine the entire system''s performance. This doesn''t work >very well, as Dom0 isn''t supposed to be heavily loaded, DomU''s are.Understandable. In my case, Dom0 would be by Desktop system while DomU would be the firewall (for now a different host), so I could live with this restriction.>3. Guest may need to be informed of the frequency change. Some kernels >may not appreciate that the CPU frequency is chaning "without it''s >knowledge". [This is probably not a big problem on modern OS''s, but some >older ones may be very un-co-operative on this account].Ah yes, I remember, that a Solaris system within VMware server didn’t like the frequency changes of the Linux host. I don’t have any problems with XP within VMware server at my notebook.>> I have an AMD64. powerno-k8 works find with non-XEN kernels, but with >> XEN-kernels I get the error: >> >> powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3400+ >> processors (version 2.00.00) >> powernow-k8: BIOS error - no PSB or ACPI _PSS objects >This is strange - as far as I can remember, I had powernow working on my >machine not so long ago (3.0.4 or so) with only the traps.c patched to >allow writing of the FID/VID controls registers.Could you send me the patch for traps.c? I would like to try it.>You''re doing this in Dom0 I take it? I don''t expect this to work in >DomU''s.Yes, of course in Dom0. For now I don’t have any DomU created. Thanks for your answers! Shade and sweet water! Stephan -- | Stephan Seitz E-Mail: Nur-Ab-Sal@gmx.de | | PGP Public Keys: http://fsing.rootsland.net/~stse/pgp.html | _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Goswin von Brederlow
2007-May-02 08:08 UTC
Re: [Xen-users] Re: Status of frequency scaling
Stephan Seitz <nur-ab-sal@gmx.de> writes:> On Mon, Apr 30, 2007 at 11:47:03AM +0200, Petersson, Mats wrote: >> Well, the current official status is "it doesn''t work at all". > > Hm, okay. > >>There are several problems, some of which are relatively easy to fix and >>some that aren''t: >>2. There is no power-management policy for the entire system, so dom0 >>usage will determine the entire system''s performance. This doesn''t work >> very well, as Dom0 isn''t supposed to be heavily loaded, DomU''s are. > > Understandable. In my case, Dom0 would be by Desktop system while DomU > would be the firewall (for now a different host), so I could live with > this restriction.It shouldn''t be too hard to write a userspace governor that check the cpu usage of all domains (like xentop does) and then scales the frequency to match. I have xen on my laptop and the batery live goes down drastically without frequency scaling (understandably). I would like to have at least manual control so I can turn the CPU down when on batery.>>3. Guest may need to be informed of the frequency change. Some kernels >>may not appreciate that the CPU frequency is chaning "without it''s >>knowledge". [This is probably not a big problem on modern OS''s, but some >> older ones may be very un-co-operative on this account]. > > Ah yes, I remember, that a Solaris system within VMware server > didnât like the frequency changes of the Linux host. > I donât have any problems with XP within VMware server at my notebook.Does Linux care?>>> I have an AMD64. powerno-k8 works find with non-XEN kernels, but >>> with XEN-kernels I get the error: >>> >>> powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3400+ processors >>> (version 2.00.00) >>> powernow-k8: BIOS error - no PSB or ACPI _PSS objects >>This is strange - as far as I can remember, I had powernow working on my >>machine not so long ago (3.0.4 or so) with only the traps.c patched to >> allow writing of the FID/VID controls registers. > > Could you send me the patch for traps.c? I would like to try it.Me too. MfG Goswin _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of > Goswin von Brederlow > Sent: 02 May 2007 09:09 > To: xen-users@lists.xensource.com > Subject: Re: [Xen-users] Re: Status of frequency scaling > > Stephan Seitz <nur-ab-sal@gmx.de> writes: > > > On Mon, Apr 30, 2007 at 11:47:03AM +0200, Petersson, Mats wrote: > >> Well, the current official status is "it doesn't work at all". > > > > Hm, okay. > > > >>There are several problems, some of which are relatively > easy to fix and > >>some that aren't: > >>2. There is no power-management policy for the entire > system, so dom0 > >>usage will determine the entire system's performance. This > doesn't work > >> very well, as Dom0 isn't supposed to be heavily loaded, DomU's are. > > > > Understandable. In my case, Dom0 would be by Desktop system > while DomU > > would be the firewall (for now a different host), so I > could live with > > this restriction. > > It shouldn't be too hard to write a userspace governor that check the > cpu usage of all domains (like xentop does) and then scales the > frequency to match.Absolutely right. It's just that no one has deemed it important enough to actually sit down and do it.> > I have xen on my laptop and the batery live goes down drastically > without frequency scaling (understandably). I would like to have at > least manual control so I can turn the CPU down when on batery. > > >>3. Guest may need to be informed of the frequency change. > Some kernels > >>may not appreciate that the CPU frequency is chaning "without it's > >>knowledge". [This is probably not a big problem on modern > OS's, but some > >> older ones may be very un-co-operative on this account]. > > > > Ah yes, I remember, that a Solaris system within VMware server > > didn’t like the frequency changes of the Linux host. > > I don’t have any problems with XP within VMware server at > my notebook. > > Does Linux care?Depends a little bit on what your doing inside linux, but in general you can run Linux with "unstable" clocks. I did that when I first wrote a PowerNow! driver for Linux (that driver, after quite a lot of modification, is now the AMD official driver, but not much of my code is there now 4 or so years later...).> > >>> I have an AMD64. powerno-k8 works find with non-XEN kernels, but > >>> with XEN-kernels I get the error: > >>> > >>> powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3400+ processors > >>> (version 2.00.00) > >>> powernow-k8: BIOS error - no PSB or ACPI _PSS objects > >>This is strange - as far as I can remember, I had powernow > working on my > >>machine not so long ago (3.0.4 or so) with only the traps.c > patched to > >> allow writing of the FID/VID controls registers. > > > > Could you send me the patch for traps.c? I would like to try it. > > Me too.Patch attached for anyone to see... It's a bit old, but I believe it still applies to traps.c. Please be aware that this code is "untested" and without any warranty of actually functioning correctly or doing what you want in any other way... -- Mats> > MfG > Goswin > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users