Hello I tried both XEN 2.0.6 and 3.0 on my ASUS M6800NE notebook. 2.0.6 - overheating and hang when start to use more CPU (ACPI is not present in this version) 3.0 - runing fine but generaly but integrated Broadcom gigabit network card is not working With both versions is not posible to use cpufreq/speefreq like utilities for CPU throtling. Based on my explorations - please can you write down your hw related xen experiences? I am planing to build server for servis DomU´s - do you have any recommendations? I am looking for something like: 2xOpteron 4GB RAM AMD or nForce4 Pro chipset RAID 1 from SATA disks Anybody has some experience with Xen stable on nForce chipset - both desktop and server version? Does it worth to use Hyperthreading on Intel when running Xen? Thanks koxman _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Having some understanding of the inner workings of the CPU''s Speed/Power handling, I can see how it would be necessary for the Xen portion to be the manager of frequency switching, as Dom0 or DomU doesn''t know what''s going on in any of the other domains per se. I guess it would technically be possible to have a monitor process in Dom0 that manages the speed of the CPU, but it''s probably better to do this in Xen itself. However, I don''t see the laptop market being a BIG portion of the Xen installations, so I''m somewhat dubious as to how much interest there would be in this [Yes, I''d love to see it done, but I''m also realistic in the expectation of this happening]. As to hyperthreading or not, I would expect it to be very dependant on the behaviour of the application, just as when you''re not running Xen. Xen will use the two HT "processors" to run on if it''s enabled. Whether this gives you more, less or the same computing power as one processor depends on what your system is doing [You can probably find a benchmark for each of those three options, if you look around a bit]. Cache-hit rate, cache-collisions, memory bandwidth and many other things will affect the performance in HT (as well as in any other processor performance scenario, of course). [By the way, it''s entirely possible to make a "proper" dual processor system run crap too, if you make sure that cache-lines are interchanged due to cache-collisions, for instance]. -- Mats _____ From: xen-users-bounces@lists.xensource.com [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of koxman Sent: 27 July 2005 07:05 To: Xen-users@lists.xensource.com Subject: [Xen-users] XEN hardware compatibility list Hello I tried both XEN 2.0.6 and 3.0 on my ASUS M6800NE notebook. 2.0.6 - overheating and hang when start to use more CPU (ACPI is not present in this version) 3.0 - runing fine but generaly but integrated Broadcom gigabit network card is not working With both versions is not posible to use cpufreq/speefreq like utilities for CPU throtling. Based on my explorations - please can you write down your hw related xen experiences? I am planing to build server for servis DomU´s - do you have any recommendations? I am looking for something like: 2xOpteron 4GB RAM AMD or nForce4 Pro chipset RAID 1 from SATA disks Anybody has some experience with Xen stable on nForce chipset - both desktop and server version? Does it worth to use Hyperthreading on Intel when running Xen? Thanks koxman _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Having some understanding of the inner workings of the CPU''s Speed/Power > handling, I can see how it would be necessary for the Xen portion to be the > manager of frequency switching, as Dom0 or DomU doesn''t know what''s going > on in any of the other domains per se. I guess it would technically be > possible to have a monitor process in Dom0 that manages the speed of the > CPU, but it''s probably better to do this in Xen itself.Yup. Another thing to consider might be providing Xen interfaces for collecting stats and setting the CPU scaling, then allow a userspace daemon (e.g. something like cpufreqd) to deal with policy. It''s a bit laptop-centric at the moment but I guess this''ll be necessary for servers, as their chips also get frequency scaling (I think there are at least some Intel chips that do this now). Of course, if you''re running Xen you should be getting high server utilisation... ;-)> However, I don''t see the laptop market being a BIG portion of the Xen > installations, so I''m somewhat dubious as to how much interest there would > be in this [Yes, I''d love to see it done, but I''m also realistic in the > expectation of this happening].*sigh* maybe one day...> As to hyperthreading or not, I would expect it to be very dependant on the > behaviour of the application, just as when you''re not running Xen. Xen will > use the two HT "processors" to run on if it''s enabled. Whether this gives > you more, less or the same computing power as one processor depends on what > your system is doing [You can probably find a benchmark for each of those > three options, if you look around a bit]. Cache-hit rate, cache-collisions, > memory bandwidth and many other things will affect the performance in HT > (as well as in any other processor performance scenario, of course). [By > the way, it''s entirely possible to make a "proper" dual processor system > run crap too, if you make sure that cache-lines are interchanged due to > cache-collisions, for instance].+1, agreed. The answer with HT is always very much "It depends". The exception is that it''s generally a good thing to run dom0 concurrently, in a separate thread from the domUs. This improves IO performance, particular on UP systems (not too sure how it fits in the Xen performance picture on SMP systems). Cheers, Mark> -- > Mats > > > _____ > > From: xen-users-bounces@lists.xensource.com > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of koxman Sent: 27 > July 2005 07:05 > To: Xen-users@lists.xensource.com > Subject: [Xen-users] XEN hardware compatibility list > > > Hello > > I tried both XEN 2.0.6 and 3.0 on my ASUS M6800NE notebook. > > 2.0.6 - overheating and hang when start to use more CPU (ACPI is not > present in this version) 3.0 - runing fine but generaly but integrated > Broadcom gigabit network card is not working > > With both versions is not posible to use cpufreq/speefreq like utilities > for CPU throtling. > > > Based on my explorations - please can you write down your hw related xen > experiences? > > I am planing to build server for servis DomU´s - do you have any > recommendations? > > I am looking for something like: > > 2xOpteron > 4GB RAM > AMD or nForce4 Pro chipset > RAID 1 from SATA disks > > Anybody has some experience with Xen stable on nForce chipset - both > desktop and server version? > > Does it worth to use Hyperthreading on Intel when running Xen? > > > Thanks > > koxman_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> -----Original Message----- > From: Mark Williamson [mailto:mark.williamson@cl.cam.ac.uk] > Sent: 27 July 2005 13:50 > To: xen-users@lists.xensource.com > Cc: Petersson, Mats; koxman > Subject: Re: [Xen-users] XEN hardware compatibility list > > > Having some understanding of the inner workings of the CPU''s > > Speed/Power handling, I can see how it would be necessary > for the Xen > > portion to be the manager of frequency switching, as Dom0 or DomU > > doesn''t know what''s going on in any of the other domains per se. I > > guess it would technically be possible to have a monitor process in > > Dom0 that manages the speed of the CPU, but it''s probably > better to do this in Xen itself. > > Yup. Another thing to consider might be providing Xen > interfaces for collecting stats and setting the CPU scaling, > then allow a userspace daemon (e.g. something like cpufreqd) > to deal with policy.Yes, if there''s an interface to get the information from Xen into (for exampl) Dom0, then we''d be able to use that for the userspace daemon, and then use a kernel module for Dom0 (or some other Dom, but it makes sense that it''s a privilige domain handling this).> > It''s a bit laptop-centric at the moment but I guess this''ll > be necessary for servers, as their chips also get frequency > scaling (I think there are at least some Intel chips that do > this now). Of course, if you''re running Xen you should be > getting high server utilisation... ;-)Yes, I''m pretty sure that there''s the Cool''n''Quiet option on AMD Opterons too (but I''m a bit removed from the products side, so I wouldn''t know exactly). However, if the server, as you suggest, is mostly in the 50-90% utilisation range, you''d probably not get that much out of it, as server workloads tend to be very transient. One of the problems with PowerNow/Cool''n''Quiet (and probably in Intels solution too, but I wouldn''t know for sure, as I haven''t worked with that technology) is that it''s somewhat costly to change the frequency, so you need many milliseconds of the same level performance before you decide to change the frequency. Do it too often, and you loose more performance due to the speed switch than you gain from increasing the speed. However, if you have a server sitting doing some work that is based on, for instance, the working day of your employees, then it would make sense to lower the CPU-speed overnight. A multinational mail-server that receives mail spread over the whole 24 hour period probably don''t get much gain from this, as it would probably be roughly at the same processing level all throughout the 24 hour period [and if it''s only running 10% performance for 90% of the time, you''d be shuffling some other load onto that machine, right?] -- Mats [snip] _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> Yes, if there''s an interface to get the information from Xen into (for > exampl) Dom0, then we''d be able to use that for the userspace daemon, > and then use a kernel module for Dom0 (or some other Dom, but it makes > sense that it''s a privilige domain handling this).Yep. It''d be nice if we could present the stats to the standard cpufreqd so that it does the right thing despite the multiple domains on the machine. Otherwise, we''d need to have a Xen-aware cpufreqd, although that shouldn''t be too hard.> Yes, I''m pretty sure that there''s the Cool''n''Quiet option on AMD > Opterons too (but I''m a bit removed from the products side, so I > wouldn''t know exactly).OK, I thought there might be.> problems with PowerNow/Cool''n''Quiet (and probably in Intels solution > too, but I wouldn''t know for sure, as I haven''t worked with that > technology) is that it''s somewhat costly to change the frequency, so youI suspect it''s still an issue. They got the resync times down quite a bit in the Dothan Pentium M but that''s a whole lot removed from their server chips.> However, if you have a server sitting doing some work that is based on, > for instance, the working day of your employees, then it would make > sense to lower the CPU-speed overnight. A multinational mail-server that > receives mail spread over the whole 24 hour period probably don''t get > much gain from this, as it would probably be roughly at the same > processing level all throughout the 24 hour period [and if it''s only > running 10% performance for 90% of the time, you''d be shuffling some > other load onto that machine, right?]Yep, indeed. CPU freq scaling will need doing at some stage but as you rightly point out, you shouldn''t have so many idle machines if you can migrate workloads around the cluster. Cheers, Mark> -- > Mats > > [snip]_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Mark Williamson wrote:> +1, agreed. The answer with HT is always very much "It depends". The > exception is that it''s generally a good thing to run dom0 concurrently, in a > separate thread from the domUs. This improves IO performance, particular on > UP systems (not too sure how it fits in the Xen performance picture on SMP > systems).As I read this, I was wondering if Xen has a boot parameter for enabling / disabling hyperthread, ala the "noht" option in linux (in fact, I cannot find the noht flag in the Linux 2.6.12 source either)? However I did come across some patches on the xen-changelog archive that refer to the noht flag, so it seems it was there at one time. Thanks, Pat -- Patrick O''Rourke porourke@egenera.com _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> > +1, agreed. The answer with HT is always very much "It > depends". The > > exception is that it''s generally a good thing to run dom0 > > concurrently, in a separate thread from the domUs. This > improves IO > > performance, particular on UP systems (not too sure how it > fits in the > > Xen performance picture on SMP systems). > > As I read this, I was wondering if Xen has a boot parameter > for enabling / disabling hyperthread, ala the "noht" option > in linux (in fact, I cannot find the noht flag in the Linux > 2.6.12 source either)? However I did come across some > patches on the xen-changelog archive that refer to the noht > flag, so it seems it was there at one time.There''s no need to disable HT on the command line -- you can choose to use it or not at run time depending on how you assign domains'' VCPUs to physical CPUs. Ian _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users