On Friday, April 24, 2015 10:24:06 PM lee wrote: > "J. Roeleveld" <jo...@antarean.org> writes: > > On Thursday, April 23, 2015 11:02:24 PM lee wrote: > >> hydra <hydrapo...@gmail.com> writes: > >> > You mean the documentation at Gentoo about Xen sucks or the upstream > >> > > >> > documentation? What information are you missing from there? Maybe we > >> > can > >> > add the missing pieces for Xen being more accessible and easier to > >> > use, > >> > what do you think? :) > >> > >> I mean the documentation they have on their wiki. It's a confusing mess > >> referring to various version with which things are being done > >> differently. > > > > The problem here is the different "implementations" that exist: > > - Xen (install and configure yourself, toolset: 'xl' , 'xm' is deprecated) > > - Citrix and XCP (pre-configured, install on dedicated server, toolset: > > 'xcp') - OVM (Oracle's implementation, not sure which toolset they use) > > Maybe, maybe not; the documentation is so confusing that I can't really > tell what it is talking about.
Where did you look? > >> Could you add missing pieces about why power management --- as in > >> frequency scaling --- doesn't work > > > > What doesn't work with this? > > The following seems quite detailed: > > http://wiki.xen.org/wiki/Xen_power_management > > There was some command to query what frequencies the CPUs are running > on, and it didn't give any output. Documentation seems to claim that > xen can do power management automagically, yet there was no way to > verify what it actually does. It works here: # xenpm get-cpufreq-para all cpu id : 0 affected_cpus : 0 cpuinfo frequency : max [3101000] min [1600000] cur [1600000] scaling_driver : acpi-cpufreq scaling_avail_gov : userspace performance powersave ondemand current_governor : ondemand ondemand specific : sampling_rate : max [10000000] min [10000] cur [20000] up_threshold : 80 scaling_avail_freq : 3101000 3100000 2900000 2700000 2500000 2300000 2100000 1900000 1700000 *1600000 scaling frequency : max [3101000] min [1600000] cur [1600000] turbo mode : enabled <snipped identical results for other CPU-cores> Looks like it's actually working and I never configured this. > > And the commands listed there (for the hypervisor based option) work on my > > server. > > > >> and what to do about keeping the time > >> in sync between all VMs when you find out that this doesn't work as the > >> documentation would have you think it does? > > > > In what way doesn't it work? > > The clocks are all synchronized and I don't need to use anything like > > 'ntpd' > The clocks were off by quite a bit after a while, and I had to use ntp > to get them in sync. Some documentation claims you don't need ntp or > anything; some other documentation apparently tries to explain that > keeping the clocks in sync cannot work unless the CPU(s) have some > features having to do with clock consistency while they are in sleep > states, and yet other documentation seems to say that using ntp cannot > work because xen screws it off. In the end, it was recommended to me to > use ntp, which I found to work. There was no way to figure out what xen > was actually doing or not doing towards this, and nobody seemed to know > how to keep the clocks in sync, other than using ntp, which appears to > be deprecated. Which version did you try? I remember having had clock-issues requiring ntp when I first started using Xen over 10 years ago. -- Joost
