Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 13 Feb 2003 06:29:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 13 Feb 2003 06:29:16 -0500 Received: from node-d-1ea6.a2000.nl ([62.195.30.166]:49391 "EHLO laptop.fenrus.com") by vger.kernel.org with ESMTP id ; Thu, 13 Feb 2003 06:29:15 -0500 Subject: Re: select returning slow on RH 2.4.18-14 (RH 8.0) kernel. From: Arjan van de Ven Reply-To: arjanv@redhat.com To: Ben Greear Cc: linux-kernel In-Reply-To: <3E4B60A1.2060209@candelatech.com> References: <3E4B60A1.2060209@candelatech.com> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-45JlsNdNHU4Rim308ESs" Organization: Red Hat, Inc. Message-Id: <1045136340.2313.1.camel@laptop.fenrus.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-1) Date: 13 Feb 2003 12:39:00 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1377 Lines: 38 --=-45JlsNdNHU4Rim308ESs Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Thu, 2003-02-13 at 10:08, Ben Greear wrote: > I've been doing some testing with RH 8.0 on an Ezra 800Mhz > machine. >=20 > Even when lightly loaded select() often returns 3-9 miliseconds slower > than the timeout would suggest. I know select is not guaranteed to > return with < 10ms accuracy, but with almost no load, shouldn't it > at least return with 1ms accuracy on average? no the kernel.org kernels will return in multiple-of-10ms quantities due to HZ having the value of 100. 2.4.18-14 (which is btw obsoleted by several security errata) has a HZ value of 512 so will return in shorter quantities, EXCEPT when you always try to wait exactly 10ms of course.... --=-45JlsNdNHU4Rim308ESs Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQA+S4PUxULwo51rQBIRAgwwAJ9UKBYIUHR2c+gFDS6LwlkMEkiQEQCfSLRh f8IjlnoIEykfrNK67vTzqlc= =ZzaC -----END PGP SIGNATURE----- --=-45JlsNdNHU4Rim308ESs-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/