From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: kvm cpu usage allocation Date: Thu, 20 Feb 2014 20:00:10 -0300 Message-ID: <20140220230010.GA16298@amt.cnet> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Alejandro Comisario Return-path: Received: from mx1.redhat.com ([209.132.183.28]:62449 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbaBUC2X (ORCPT ); Thu, 20 Feb 2014 21:28:23 -0500 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Feb 19, 2014 at 06:42:56PM -0300, Alejandro Comisario wrote: > Hi everyone. > We are having a private cloud with more than 1000 phy servers. > Each server has 128GB of RAM and 24 cores (2 heaxacores with HT > enabled), but the amount of vms running on those servers versus the > flavor (amount of CPU) made us use about 80 VCPUS. > > The questions are as follow. > > * is there a fine documentation of HOW kvm handles cpu allocation/pin > per vm in an scenario like this one ? > * is there also, a documentation that explains under a circumstance > where a VM needs more processing power, how priority is managed ? > * is there a way to define some kind of politics or rules to have > specific cpu pinning for specific vms ? Hi Alejandro, Check "Chapter 7. Overcommitting with KVM" of https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/chap-Virtualization-Tips_and_tricks-Overcommitting_with_KVM.html