From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4450B2B8.1060800@domain.hid> Date: Thu, 27 Apr 2006 14:02:00 +0200 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-core] Latencies for the Freescale i.MX21/CSB535FS References: In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig12BF1A5765DACC72BE149013" List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: ROSSIER Daniel Cc: xenomai@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig12BF1A5765DACC72BE149013 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable ROSSIER Daniel wrote: >> >> I'd say that the most efficient way to reduce those latencies would >> require to first identify the source of the 40+ us spot observed with >> the -t2 form on an idle system. For that, I'm convinced that porting t= he >> I-pipe tracer to ARM would be the best option, since this tool would b= e >> of great help there. >> > Thanks for the hint; we will spend some time on the tracer in the comin= g days. We keep you informed. >=20 Cool, tracing also for ARM! >> This port basically requires 1) to code the mcount() routine supportin= g >> gcc's -pg option, 2) to solve early boot issues so that mcount() does >> not attempt to trace anything while the memory environment has not bee= n >> fully set up. The rest is pretty generic. >> Regarding a mcount() implementation and other details, the original tracer effort by Ingo Molnar may give useful hints (at least it did for m= e): http://people.redhat.com/mingo/latency-tracing-patches/ I remember the ARM part not being that simple as x86. I think this was also due to lacking stack unwinding support on that arch. Jan --------------enig12BF1A5765DACC72BE149013 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 iD8DBQFEULK4ncNeS9Q0k+IRAuFvAKDbT869Ei1vWTe+GiGOldqr0Tn3DACfcZgz K9QWc3YjQZyxc6vrn1hCkvc= =FwgT -----END PGP SIGNATURE----- --------------enig12BF1A5765DACC72BE149013--