From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luis R. Rodriguez" Subject: Re: Xen default install - no cpufreq on dom0 ? Date: Tue, 23 Feb 2016 23:18:09 +0100 Message-ID: <20160223221809.GI25240@wotan.suse.de> References: <20160223220012.GB17927@char.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160223220012.GB17927@char.us.oracle.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Konrad Rzeszutek Wilk Cc: "Luis R. Rodriguez" , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Tue, Feb 23, 2016 at 05:00:12PM -0500, Konrad Rzeszutek Wilk wrote: > On Tue, Feb 23, 2016 at 12:48:18PM -0800, Luis R. Rodriguez wrote: > > For a while now I've been installing Xen from source on my Debian box, > > with a default configuration always. This is party why I've run into > > compile issues before it seems, but I've also just picked up on > > another possible issue. My system on dom0 overheats and shuts itself > > off. For a while I didn't think this was Xen related and perhaps > > related to the fact that I built this system myself. However, after > > running Debian without Xen (rm -rf /boot/xen*; update-grub; reboot; > > systemd-detect-virt yield none) it would seem this does not happen. > > What's a bit concerning though is even if I run offlineimap in > > singlethreaded mode (offlineimap -1) the machine overheats and shuts > > itself off, so I don't necessarily need to be doing a lot of work. I > > tried compiling the kernel without Xen while running offlineimap as > > well with make -j 8 and it doesn't overheat, meanwhile on Xen dom0 > > just using offlineimap -1 seems to trigger a shutoff rather quickly. > > What exactly triggers the shutoff. Clearly, overheating. I'm not yet sure if its just BIOS/kernel/hypervisor induced forced shutdown. Will try again, but this is rather intrusive as its on my personal home system. > > The kernel has: > > > > CONFIG_CPU_FREQ_GOV_PERFORMANCE=y > > > > I tried on /etc/default/grub > > > > GRUB_CMDLINE_LINUX_XEN_REPLACE="cpufreq=dom0-kernel" > > > > But that didn't help. This is running 4.5.0-rc2 and the latest Xen I > > was able to build (I try xen staging tree always). > > Right. We are actually going to remove that option as it makes no sense > for Linux (dom0) to control the cpu frequency. > > Irrespective of that - there are simply no drivers in dom0 that would > do the cpufreq for you (unless you recompile the kernel and edit in > arch/x86/xen/enlighten.c the calls to disable cpuidle and cpufreq code). How can I (and Xen by default) not overheat a system then ? What's the short term and long term plan? I was a bit surprised a simple single threaded offlineimap would force a shutoff on Xen. I figured I must be seriously misconfiguring something but this is just running with defaults. Luis