From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: Strange interdependace between domains Date: Tue, 18 Feb 2014 17:55:49 +0100 Message-ID: <1392742549.32038.580.camel@Solace> References: <1646915994.20140213165604@gmail.com> <1392313015.32038.112.camel@Solace> <295276356.20140213222507@gmail.com> <6010385428.20140214120238@gmail.com> <1392398466.32038.334.camel@Solace> <752791084.20140217124616@gmail.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============4571835881833689328==" Return-path: In-Reply-To: <752791084.20140217124616@gmail.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: Simon Martin Cc: Andrew Cooper , Ian Campbell , Nate Studer , Don Slutz , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org --===============4571835881833689328== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-h+Z7qroTDMvlfRFoksZV" --=-h+Z7qroTDMvlfRFoksZV Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On lun, 2014-02-17 at 12:46 +0000, Simon Martin wrote: > Hyperthreading is just a way to improve CPU resource utilization. Even > if you are doing a CPU intensive operation, a lot of the processor > circuits are actually idle, so adding 2 pipelines to feed one > processor is a good way to improve total throughput, but it does have > it have it's caveats. I totally forgot this. >=20 > Given the way that this works there isn't much that Xen can do. It is > a physical restriction. >=20 I know, and my point was not that we should try to "fix" in Xen, what's impossible to fix, because it's just how hardware works... and that is by design! I was only saying that there are cases, when you still need isolation, but you can afford a bit more of uncertainty, there is the possibility for Xen to at least try to do the right thing automagically. Basically, I'm ok with people looking for hard real-time response time and jitter to have to pick up the proper hw platform, as a first step, and properly fine tune it. For more _soft_ real-time workloads, I wish we were (think we should be) able to do better, perhaps still with some user required tweaks, but nothing equally intrusive, that's it. :-) > OK. This is my current configuration: >=20 > Dom0 PCPU 0,1,2 no pinning > win7x64 PCPU 1,2 pinned > pv499 PCPU 3 pinned >=20 > And I get the same interdependence. >=20 > root@smartin-xen:~# xl list > Name ID Mem VCPUs State T= ime(s) > Domain-0 0 1253 3 r----- = 37.1 > win7x64 4 2046 2 ------ = 106.8 > pv499 5 128 1 r----- = 66.8 > root@smartin-xen:~# xl vcpu-list=20 > Name ID VCPU CPU State Time(s) CPU Af= finity > Domain-0 0 0 1 -b- 21.2 all > Domain-0 0 1 2 r-- 8.8 all > Domain-0 0 2 0 -b- 8.2 all > win7x64 4 0 1 -b- 59.8 1 > win7x64 4 1 2 -b- 49.0 2 > pv499 5 0 3 r-- 70.2 3 > root@smartin-xen:~# xl cpupool-list -c > Name CPU list > Pool-0 0,1,2 > pv499 3 >=20 > I have gone back to my working settings. >=20 Ok, thanks a lot for trying. I was hoping for that tweak, although developed for completely different reasons, to be helpful in this case, but it appears it is not. Probably, I wouldn't have pinned the two win7 vcpus either, but anyway, I don't want to eat any more of your time... Glad you find a configuration that is working out! :-) Thanks again and Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-h+Z7qroTDMvlfRFoksZV Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEABECAAYFAlMDkJUACgkQk4XaBE3IOsQFGACeKYce6icMxBcX2x00VvYScNAA d8gAn3fk18FzppSVgGOeYBd5uv+7kYLY =hX3O -----END PGP SIGNATURE----- --=-h+Z7qroTDMvlfRFoksZV-- --===============4571835881833689328== 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 --===============4571835881833689328==--