From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <44172B67.2000609@domain.hid> Date: Tue, 14 Mar 2006 21:45:27 +0100 From: Jan Kiszka MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigAA08748D591C0C8280D4A1D2" Sender: jan.kiszka@domain.hid Subject: [Xenomai-core] Synchronising TSC and periodic timer List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai-core This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigAA08748D591C0C8280D4A1D2 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Hi, for those who haven't followed the endless "RTDM and Timer functions" thread: we are currently discussing a way to provide high-resolution timestamps in periodic mode for RTDM users. It was suggested to use the TSC for this, but I noted that this source will not be in sync with the periodic system timer and may even be out of sync across multiple CPUs. A straight-forward approach to overcome this might be to record the current TSC value together with the current jiffies in xntimer_do_tick_periodic(). This tuple (per CPU) could then be provided to skin implementers in order to let them offer a high-resolution timestamp source even in periodic mode. Hmm, sounds too simple actually, so I'm waiting now for someone pointing out the pitfalls. Jan --------------enigAA08748D591C0C8280D4A1D2 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 iD8DBQFEFytnniDOoMHTA+kRAhrnAJ9VT1kQZUFpE6ymvycGzGl3+m+o6ACfWiwG i3EtLCVQzcO6UZ7uJX4Fcgg= =empD -----END PGP SIGNATURE----- --------------enigAA08748D591C0C8280D4A1D2--