From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4BB5B1BD.6020903@domain.hid> Date: Fri, 02 Apr 2010 10:58:37 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <20100401230843.GF3755@domain.hid> <4BB53566.3010601@domain.hid> <4BB53643.2080604@domain.hid> <4BB5AA44.6000006@domain.hid> <4BB5AACE.7020602@domain.hid> In-Reply-To: <4BB5AACE.7020602@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig06C83E7DC0DFD867F1C77345" Sender: jan.kiszka@domain.hid Subject: Re: [Xenomai-help] New scheduler class 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 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig06C83E7DC0DFD867F1C77345 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Gilles Chanteperdrix wrote: >>> Jan Kiszka wrote: >>>> Andreas Glatz wrote: >>>>> Hi Philippe, >>>>> >>>>> At the Xenomai Users Meeting last year I asked you if Xenomai would= offer a possibility to lower the priority of certain Xenomai tasks below= that of Linux. We need this feature since we have tasks in our RT applic= ation which should only run when Linux is idle (A statistics collection t= ask which part of the RT application and hard to isolate from this applic= ation). >>>>> >>>> What prevents using a borderline thread (if you need to interact wit= h >>>> blocking Xenomai services) with SCHED_OTHER and a Linux nice level o= f 19? >>> Well, this does not really guarantee that the thread will run only wh= en >>> linux is idle. The thread will eat some cpu time, the nice level is n= ot >>> a strict priority, as you know. >> Where do you really need anything stricter? It's the opposite of "I ne= ed >> true 100% CPU for my task, and that forever." >> >>> But in fact, I wonder why Andreas wants >>> a new scheduling policy for xenomai, what is needed, is simply a >>> SCHED_IDLE (maybe it exists ?!) policy for Linux. >>> >> There is no such thing AFAIK. If you are concerned that some CPU >> intensive low prio job eats too much CPU, you normally reduce its >> nice-level and/or confine its CPU bandwidth via cgroups. >=20 > SCHED_IDLE exists. >=20 Ah, as "nice 20". Same mechanism, just another level. Jan --------------enig06C83E7DC0DFD867F1C77345 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 iEYEARECAAYFAku1scEACgkQitSsb3rl5xSRGgCg7yCIIEkffDU3lkmVhHg7jt4Z HrkAniq0+HuAls1rXgWW5zyF4luDYAsB =hf4w -----END PGP SIGNATURE----- --------------enig06C83E7DC0DFD867F1C77345--