From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: Status of Credit2 and Credit1 [was: Re: Xen 4.6 Development Update (four months reminder)] Date: Wed, 20 May 2015 23:09:39 +0200 Message-ID: <1432156179.7907.3.camel@citrix.com> References: <1431738921.2978.215.camel@citrix.com> <20150519173511.GT26335@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5455568336124730142==" Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1YvBFL-0004qF-7I for xen-devel@lists.xenproject.org; Wed, 20 May 2015 21:09:47 +0000 In-Reply-To: <20150519173511.GT26335@zion.uk.xensource.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: Wei Liu Cc: "george.dunlap@eu.citrix.com" , xen-devel@lists.xenproject.org, jtweaver@hawaii.edu List-Id: xen-devel@lists.xenproject.org --===============5455568336124730142== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-Zq/2WDgPRlxcsGZoFPQ5" --=-Zq/2WDgPRlxcsGZoFPQ5 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2015-05-19 at 18:35 +0100, Wei Liu wrote: > On Sat, May 16, 2015 at 03:15:21AM +0200, Dario Faggioli wrote: > > > =3D=3D=3D Hypervisor X86 =3D=3D=3D=20 > >=20 > > > * HT enabled with credit has 7.9 per perf drop. (none) > > > kernbench demonstrated it > > > http://www.gossamer-threads.com/lists/xen/devel/339409 > > > This has existed since credit1 introduction. > > > - Dario Faggioli > > > > > Let me clarify this a bit. > >=20 > > First of all, let me point out that the issue only shows up in > > under-loaded systems (i.e., with less active vcPUs then the host has > > pCPUs). In any case, this is something inherent in Credit1 architecture= , > > and I don't have a sensible idea on how to deal with it without causing > > other problems. > >=20 > > I am working on some improvement to Credit1 (e.g., introducing load > > tracking and basing some decisions on it), which hopefully will help > > better performance even in this case, but I'm not actively working on > > fixing this (if it can be fixed). > >=20 >=20 > I have moved this to deferred section. Is this OK? >=20 Sounds good, thanks. Regards, Dario --=-Zq/2WDgPRlxcsGZoFPQ5 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 v2 iEYEABECAAYFAlVc+BMACgkQk4XaBE3IOsRkhACeNYRfoGCPlSmYOba1fLl5MOi+ jWgAnAwMo8cgAkD1KHHxSior7WLcXRbc =rlp4 -----END PGP SIGNATURE----- --=-Zq/2WDgPRlxcsGZoFPQ5-- --===============5455568336124730142== 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 --===============5455568336124730142==--