From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4994A9EF.9070108@domain.hid> Date: Thu, 12 Feb 2009 23:59:59 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <7ed3bc8b0902120904r800de72q97e694001600051e@domain.hid> <499480EE.3040403@domain.hid> <49948E51.9000509@domain.hid> <49949E48.4010106@domain.hid> <4994A180.3020102@domain.hid> <4994A261.5050003@domain.hid> In-Reply-To: <4994A261.5050003@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig7109E673420E30E447AEC44B" Sender: jan.kiszka@domain.hid Subject: Re: [Xenomai-help] Known-to-work motherboards? List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: xenomai@xenomai.org, Stuart O Anderson This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig7109E673420E30E447AEC44B Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Gilles Chanteperdrix wrote: >>>>> Stuart O Anderson wrote: >>>>>> If there isn't a list online that I've missed, is anyone running >>>>>> xenomai on a relatively recent machine with 8 or more cores withou= t >>>>>> problems? If so, can you provide hardware specs? >>>>> Xenomai will have scalability problems when running on an 8 cores s= ystem >>>>> (if you intend to run real-time tasks on each of the 8 cores). >>>>> >>>> We are running Xenomai on up to 4x4 boxes, but only with 1 or 2 core= s >>>> used by RT tasks. I've some patch hanging around that restricts Xeno= mai >>>> (specifically its host timer hook) to a CPU subset in order to mitig= ate >>>> the scalability issues - guess I should finally get it in shape and = post it. >>> The host timer already runs on only one CPU. >> Not on x86. >=20 > Some time ago, when using the APIC (which was always the case on x86 > SMP), the host timer was not even started, and the Linux APIC irqs were= > triggered by a custom 8254 irq handler. Well, it seems things have > changed since then... =2E..around the Linux clocksource/clockevent rework. And it also makes more sense with the number of cores increasing and NUMA becoming standard. CPU-local timers are simply more efficient. That's why the nklock hurts that any host tick must pass even if the core is not used by Xenomai otherwise. Jan --------------enig7109E673420E30E447AEC44B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.9 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iEYEARECAAYFAkmUqfMACgkQniDOoMHTA+lKKQCffV/+L+Q2LpxCQLkNMg1X3dKm j/sAnR+OZCdfbLG6jEFwJaKQDd3ntJUc =Bj+7 -----END PGP SIGNATURE----- --------------enig7109E673420E30E447AEC44B--