From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45538D53.5090305@domain.hid> Date: Thu, 09 Nov 2006 21:19:31 +0100 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-core] I-pipe patch for ARM S3C24xx (v4) References: In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig92B02502A92EA1EF0204C0F8" Sender: jan.kiszka@domain.hid List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sebastian Smolorz Cc: xenomai-core This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig92B02502A92EA1EF0204C0F8 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Sebastian Smolorz wrote: > Hi all, >=20 > now that the teething problems of my I-pipe port to the S3C24xx are cur= ed=20 > (hopefully ...) I'm going to iterate it to v4. We've established a proj= ect=20 > homepage for that port > http://opensource.emlix.com/ipipe-s3c24xx/ > in order to concentrate the source code and information at one point. P= robably=20 > tomorrow I will come up with a patch in order to address point 2 in my = email=20 > from 27.10.2006 ([1]). After that I can go to v5 of my patch and beg fo= r=20 > integration. :-) Nice to hear. >=20 > However, there is one disturbing issue. When I execute >=20 > dd if=3D/dev/zero of=3D/dev/null >=20 > and the latency test in userspace with a period not less than 150 us th= e worst=20 > case latency is about 220 us. But when I start latency with -p 100 I ge= t a=20 > softlock like the one attached. I guess this is the same problem as Det= lef=20 > Vollmann described in [2]. So I think it's time for a big fat ARM-speci= fic=20 > warning in the troubleshooting file and perhaps a modification of the=20 > testsuite so that if being compiled for ARM the default sample periods = are=20 > greater than the 100 us now. Something is preventing the watchdog kthread from being executed for more than 10 s. Maybe this is just a sign that the systems is hopelessly overloaded (what are average latencies?). Maybe it is a real IRQ or scheduling issue in Linux caused by I-pipe. Maybe it is time to port the I-pipe tracer... ;) Jan --------------enig92B02502A92EA1EF0204C0F8 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFFU41TniDOoMHTA+kRAt1pAJwMJkAY0P6X7v+151IsayJdZA/OAQCfaP+J O3ElW8ruGEGlN2FwVBrk2FM= =popJ -----END PGP SIGNATURE----- --------------enig92B02502A92EA1EF0204C0F8--