From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zir Blazer Subject: Re: (no subject) Date: Thu, 13 Feb 2014 20:47:12 -0300 Message-ID: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0853339934329388111==" Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org --===============0853339934329388111== Content-Type: multipart/alternative; boundary="_df9db6c2-0843-4bed-b94c-8e82ecbe69d4_" --_df9db6c2-0843-4bed-b94c-8e82ecbe69d4_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable >> I can't understand this as disk activity should be running on cores 0=2C= >> 1 and 2=2C but never on core 3. The only thing running on core 3 should= >> by my paravirtual machine and the hypervisor stub.>>>> Any idea what's g= oing on? Your Core i3 is a Dual Core Processor with Hyper Threading. Hyper Threading= allows each Core to run two Threads simultaneously=2C in what is called ph= ysical Core and virtual Core (Or around those lines=2C but you get the idea= ). They share resources=2C and the extra Thread actually gets the free reso= urces/execution time that weren't used by the main Thread. As Core 3 is the= virtual core of the physical Core 2 (Assuming that on Linux it sees and nu= mbers them as Physical Core 0=2C Logical Core 1=2C Physical Core 2 and Logi= cal Core 3 and so on)=2C you're giving that VM just a spare virtual Core wi= th the free resources that weren't used by the physical Core. You should tr= y with a full physical Core (Core 2 and 3)=2C otherwise whatever runs on Co= re 2 WILL impact heavily what you see on Core 3. = --_df9db6c2-0843-4bed-b94c-8e82ecbe69d4_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
>=3B>=3B I can't unders= tand this as disk activity should be running on cores 0=2C
>=3B= >=3B 1  =3Band 2=2C but never on core 3. The only thing running on co= re 3 should
>=3B>=3B by my paravirtual machine and the hyperv= isor stub.
>=3B>=3B
>=3B>=3B Any idea what's go= ing on?

Your Core i3 is a Dual Core Processor with= Hyper Threading. Hyper Threading allows each Core to run two Threads simul= taneously=2C in what is called physical Core and virtual Core (Or around th= ose lines=2C but you get the idea). They share resources=2C and the extra T= hread actually gets the free resources/execution time that weren't used by = the main Thread. As Core 3 is the virtual core of the physical Core 2 (Assu= ming that on Linux it sees and numbers them as Physical Core 0=2C Logical C= ore 1=2C =3BPhysical Core 2 and Logi= cal Core 3 and so on)=2C you're giving that VM just a spare virtual Core wi= th the free resources that weren't used by the physical Core. You should tr= y with a full physical Core (Core 2 and 3)=2C otherwise whatever runs on Co= re 2 WILL impact heavily what you see on Core 3.
= --_df9db6c2-0843-4bed-b94c-8e82ecbe69d4_-- --===============0853339934329388111== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel --===============0853339934329388111==--