From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4BB5AA44.6000006@domain.hid> Date: Fri, 02 Apr 2010 10:26:44 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <20100401230843.GF3755@domain.hid> <4BB53566.3010601@domain.hid> <4BB53643.2080604@domain.hid> In-Reply-To: <4BB53643.2080604@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0840A3301C4E1934E9169B53" 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) --------------enig0840A3301C4E1934E9169B53 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Gilles Chanteperdrix wrote: > Jan Kiszka wrote: >> Andreas Glatz wrote: >>> Hi Philippe, >>> >>> At the Xenomai Users Meeting last year I asked you if Xenomai would o= ffer a possibility to lower the priority of certain Xenomai tasks below t= hat of Linux. We need this feature since we have tasks in our RT applicat= ion which should only run when Linux is idle (A statistics collection tas= k which part of the RT application and hard to isolate from this applicat= ion). >>> >> What prevents using a borderline thread (if you need to interact with >> blocking Xenomai services) with SCHED_OTHER and a Linux nice level of = 19? >=20 > Well, this does not really guarantee that the thread will run only when= > linux is idle. The thread will eat some cpu time, the nice level is not= > a strict priority, as you know. Where do you really need anything stricter? It's the opposite of "I need 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. >=20 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. Jan --------------enig0840A3301C4E1934E9169B53 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 iEYEARECAAYFAku1qkoACgkQitSsb3rl5xSnlgCghbk3LVsirsEWaVx+sKDIJoGw eYcAn0GDy2T5gCLQTCX+dbjQPF4N5AAW =A1yX -----END PGP SIGNATURE----- --------------enig0840A3301C4E1934E9169B53--