From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <44CF691C.30706@domain.hid> Date: Tue, 01 Aug 2006 16:45:48 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <442248c90607201417m24729b7cs23a8b82b719ff1cc@domain.hid> <200607221152.34298.bidsonux@domain.hid> <44C25DB0.50601@domain.hid> <200607282317.34990.bidsonux@domain.hid> <44CB6EB3.5070707@domain.hid> <1154282619.4970.25.camel@domain.hid> <44CD099F.9010507@domain.hid> <1154294584.4970.49.camel@domain.hid> <17613.60380.820599.627459@domain.hid> <1154355564.5015.12.camel@domain.hid> <1154442627.4963.21.camel@domain.hid> In-Reply-To: <1154442627.4963.21.camel@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB4726B93D21E90E8C7A50F75" Sender: jan.kiszka@domain.hid Subject: [Xenomai-core] [RFC] tame the watchdog (was: Beginner's question / testsuite / latency) List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: rpm@xenomai.org, xenomai@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB4726B93D21E90E8C7A50F75 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Philippe Gerum wrote: >> Still, reinitializing X while the latency test runs causes >> the latter to hang, albeit LOC is still flowing properly and the box >> keeps going normally. >=20 > This one was due to the nucleus watchdog which triggered right after th= e > graphic mode was fully initialized, due to the huge amount of > unpreemptible time spent doing this; this caused the sampling task to b= e > detected as a runaway thread. So the behaviour is ok, albeit a bit > frightening at first. >=20 That reminds of the unfortunate characteristics of the 2.6 oom-killer: unless you set your time-critical app's oom_adj to -17, you are never really safe from being killed accidentally on low-mem scenarios. What about introducing some mechanism to protect audited tasks against the watchdog? A simple thread flag settable via existing APIs, ignored if there is no watchdog compiled in? Jan --------------enigB4726B93D21E90E8C7A50F75 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFEz2kcniDOoMHTA+kRAiviAJ46gjMHIpOqUEZ3cn6lr1FTio/ubgCfcprV qPvBWhG9wj5ucn/1yqoZTFg= =sL1B -----END PGP SIGNATURE----- --------------enigB4726B93D21E90E8C7A50F75--