From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <440442FC.8090100@domain.hid> Date: Tue, 28 Feb 2006 13:33:00 +0100 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Xenomai-help] negative values of latency/klatency References: <440324EE.6030309@domain.hid> In-Reply-To: <440324EE.6030309@domain.hid> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB67A1871FA106F628B7921C1" Sender: jan.kiszka@domain.hid List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Rudolf Marek Cc: xenomai@xenomai.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigB67A1871FA106F628B7921C1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Rudolf Marek wrote: > Hello all, >=20 > I tried the latency and klatency demo on some PPC procesor(s) (e500 and= 60x) and the measurement results are rather strange. > I observed this with arbitrary version of Adeos/ipipe and on Xenomai 2.= 0.3 older 2.0.x too. >=20 > -sh-3.00# ./run -- -T 10 -h -l 5 > ... > RTT| 00:00:01 > RTH|----klat min|----klat avg|----klat max| overrun|---klat best|--klat= worst > RTD| -4525| -4323| 5777| 0| -4525| = 5777 > RTD| -4525| -4444| -1777| 0| -4525| = 5777 > RTD| -4525| -4444| -565| 0| -4525| = 5777 > RTD| -4525| -4444| -1656| 0| -4525| = 5777 > RTD| -4525| -4444| -1979| 0| -4525| = 5777 > RTT| 00:00:06 > RTH|----klat min|----klat avg|----klat max| overrun|---klat best|--klat= worst > RTD| -4525| -4444| -2020| 0| -4525| = 5777 > RTD| -4525| -4444| -1050| 0| -4525| = 5777 > RTD| -4525| -4444| -1616| 0| -4525| = 5777 > RTD| -4525| -4444| -1898| 0| -4525| = 5777 > RTD| -4525| -4444| -1939| 0| -4525| = 5777 > ... > Well if I set scheduling latency from automatic "0" to "1" I get: 0 means automatic latency compensation (which does not seem to work that well here, it overcompensates), while 1 effectively means "no hardware/software scheduling latency" (=3D> 1 ns). See also help of the related kernel configuration parameters. >=20 > -sh-3.00# ./run -- -T 10 -h -l 5 >=20 > RTT| 00:00:01 > RTH|----klat min|----klat avg|----klat max| overrun|---klat best|--klat= worst > RTD| 4767| 4929| 15191| 0| 4767| = 15191 > RTD| 4767| 4808| 8282| 0| 4767| = 15191 > RTD| 4767| 4808| 8080| 0| 4767| = 15191 > RTD| 4808| 4808| 7838| 0| 4767| = 15191 > RTD| 4767| 4808| 7272| 0| 4767| = 15191 > RTT| 00:00:06 > RTH|----klat min|----klat avg|----klat max| overrun|---klat best|--klat= worst > RTD| 4808| 4808| 7555| 0| 4767| = 15191 > RTD| 4767| 4808| 7959| 0| 4767| = 15191 > RTD| 4767| 4808| 7393| 0| 4767| = 15191 > RTD| 4808| 4808| 7191| 0| 4767| = 15191 > RTD| 4767| 4808| 7313| 0| 4767| = 15191 >=20 > Is this a bug or feature please? Can someone throw the light? > Good would be to print the units to the numbers too (ns). >=20 That was likely a layout question of the latency tool's output. We could simply dump something like "All latencies in nanoseconds" during start-up. Would this be more helpful? Jan --------------enigB67A1871FA106F628B7921C1 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 iD8DBQFEBEL8niDOoMHTA+kRAqhMAJ9NlZwT9/ocriddkuQOe6UiFMbVOACeKk0T yT2UxoayMmvHQI4Y8Vh5Mac= =gY4I -----END PGP SIGNATURE----- --------------enigB67A1871FA106F628B7921C1--