From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: smp guest questions Date: Wed, 17 Jun 2009 14:46:47 +0400 Message-ID: <4A38C997.5020005@msgid.tls.msk.ru> References: <4A38ABA3.2010401@msgid.tls.msk.ru> <4A38B43E.6010704@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM list , Marcelo Tosatti To: Avi Kivity Return-path: Received: from isrv.corpit.ru ([81.13.33.159]:57369 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbZFQKqs (ORCPT ); Wed, 17 Jun 2009 06:46:48 -0400 In-Reply-To: <4A38B43E.6010704@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > On 06/17/2009 11:38 AM, Michael Tokarev wrote: >> After seeing words from Avi about that smp guests >> are ok now, I descided to try. And immediately >> got a few questions. >> >> Running on a Phenom 9750 machine (PhenomI), AMD780G >> chipset. Host is 2.6.29 x86-64, qemu-kvm 0.10.5, >> guests are linux with kvm paravirt bits enabled, also >> dynticks (on both host and guest). >> >> >> When booting a 2-CPU guest, I see in dmesg: >> >> PM-Timer running at invalid rate: 200% of normal - aborting. >> >> and indeed, in available_clocksource there's no pmtimer. >> Should I be concerned? It does not look healthy. >> > > It's a bug, please post guest details (kernel version, bitness). The guest kernel is also 2.6.29[.5], but this time it's x86-32 (compiled for P4). kvm userspace is also 32bits (historical) -- only host kernel is 64bit for now. I'll try to do some more experiments later today on a test machine (this is a production box) -- "hopefully" that same issue will occur on another machine :) > Copying Marcelo. > >> >> Some time later, I see stuff like: >> >> hrtimer: interrupt too slow, forcing clock min delta to 47210997 ns >> >> Which reminds me issues I had with broken hpet (time goes >> back-n-forth with similar messages shown in dmesg, but >> about hpet not hrtimer). Also does not look healthy. >> >> >> I haven't seen either of the two messages above on any of >> single-processor guests so far, at least with recent kernels >> and kvm userspace, only on smp (2 cpu for now). > > Please also post host /proc/cpuifo. HOST cpuinfo (only for 4th core, other cores are similar): processor : 3 vendor_id : AuthenticAMD cpu family : 16 model : 2 model name : AMD Phenom(tm) 9750 Quad-Core Processor stepping : 3 cpu MHz : 1200.000 (yes ondemand cpufreq is in effect - nominal frequency is 2400. I had no issues with cpufreq on this box so far, including all the guests). cache size : 512 KB physical id : 0 siblings : 4 core id : 3 cpu cores : 4 apicid : 3 initial apicid : 3 fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni monitor cx16 lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs bogomips : 4812.67 TLB size : 1024 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm stc 100mhzsteps hwpstate cpuinfo on GUEST (also for only one CPU): processor : 1 vendor_id : AuthenticAMD cpu family : 6 model : 2 model name : QEMU Virtual CPU version 0.10.5 stepping : 3 cpu MHz : 2405.894 cache size : 512 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall lm pni hypervisor bogomips : 4811.78 clflush size : 64 power management: Thanks! /mjt