From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: Re: ARINC653 Date: Mon, 9 Dec 2013 22:28:05 +0100 Message-ID: <1386624485.14872.10.camel@Abyss> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5531356438188439667==" Return-path: In-Reply-To: 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 , josh.whitehead@dornerworks.com, Nate Studer , Robbie VanVossen , xen-devel List-Id: xen-devel@lists.xenproject.org --===============5531356438188439667== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-tE3RElsCuQm/PgonuDhS" --=-tE3RElsCuQm/PgonuDhS Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On lun, 2013-12-09 at 20:23 +0000, Simon Martin wrote: > smartin@smartin-xen:~/projects/trio/xen/pv499$ sudo xl cpupool-list > Name CPUs Sched Active Domain count > Pool-0 3 credit y 1 > pv499 1 arinc653 y 1 > Ok, which pcpus are in each pool? In theory, it shouldn't matter, but, you know... :-P =20 > After loading the domU into the pv499 and running the program that > configures the arinc scheduler I get this: > =20 > smartin@smartin-xen:~/projects/trio/xen/pv499$ sudo xl list > Name ID Mem VCPUs State > Time(s) > Domain-0 0 2967 4 r----- > 117.2 > pv499 24 32 1 r----- > 373.0 > =20 > So far so good. Now looking at the timings things are not too > different from when I was using the credit scheduler. Running a single > shot timer at a period of 250 =C2=B5s gives me a jitter in the timer > handler latency in the range [3.5 =C2=B5s, 45 =C2=B5s]. This makes it loo= k like > the problem in the jitter is not the scheduling but the underlying > hypervisor. It is going off to do things on this CPU which is causing > the deadlines not to be met. > =20 > So unless I am doing something silly it looks like I will have to go > to RT-Xen to get better timings. For the moment I'm going to leave > this and go on to getting more of my operating system working. > Well, RT-Xen is a great project, but it's mostly, if not all, about scheduling. I mean, all they do is introducing two new schedulers (with a couple of operational mode in each), and that's it... There is nothing there being done for reducing latency or jitter. I think, we'd better off (as soon as, as you said, you have more pieces in place), trying to figure out what is causing the behavior you're seeing and workaround/fix/amend it! It's a busy period, with the 4.4 release, etc., but, as repeatedly said, I'm up for helping with this, if help is needed! :-P Regards, Dario --=20 <> (Raistlin Majere) ----------------------------------------------------------------- Dario Faggioli, Ph.D, http://about.me/dario.faggioli Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK) --=-tE3RElsCuQm/PgonuDhS 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 v1.4.15 (GNU/Linux) iEYEABECAAYFAlKmNeUACgkQk4XaBE3IOsTBrwCcC3D1qBib5wJE1ZLWjmPuNFJT xrwAn28/VHilB/sR8C748540b2ucY8AU =ppwB -----END PGP SIGNATURE----- --=-tE3RElsCuQm/PgonuDhS-- --===============5531356438188439667== 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 --===============5531356438188439667==--