Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262140AbVEYKwY (ORCPT ); Wed, 25 May 2005 06:52:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262144AbVEYKwY (ORCPT ); Wed, 25 May 2005 06:52:24 -0400 Received: from mail03.syd.optusnet.com.au ([211.29.132.184]:54212 "EHLO mail03.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S262140AbVEYKwR (ORCPT ); Wed, 25 May 2005 06:52:17 -0400 From: Con Kolivas To: Ingo Molnar Subject: Re: RT patch acceptance Date: Wed, 25 May 2005 20:51:52 +1000 User-Agent: KMail/1.8 Cc: Nick Piggin , Andrew Morton , Sven Dietrich , dwalker@mvista.com, bhuey@lnxw.com, hch@infradead.org, linux-kernel@vger.kernel.org References: <1116978244.19926.41.camel@dhcp153.mvista.com> <20050524184351.47d1a147. <20050525074633.GA18423@elte.hu> In-Reply-To: <20050525074633.GA18423@elte.hu> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1842854.eT49bHCjT8"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200505252051.55544.kernel@kolivas.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2334 Lines: 60 --nextPart1842854.eT49bHCjT8 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Wed, 25 May 2005 17:46, Ingo Molnar wrote: > * Nick Piggin wrote: > > >i agree in theory, but interestingly, people who use the -RT branch do > > >report a smoother desktop experience. While it might also be a > > >psychological effect, under -RT an interactive X process has the same > > >kind of latency properties as if all of the mouse pointer input and > > >rendering was done in the kernel (like some other desktop OSs do). > > > > > >so in terms of mouse pointer 'smoothness', it might very well be > > >possible for humans to detect a couple of msec delays visually - even > > >though they are unable to notice those delays directly. (Isnt there so= me > > >existing research on this?) > > > > I'm guessing not, just because the monitor probably hasn't even > > refreshed at that point ;) But... > > this reminds me, people very much notice the difference between an LCD > that has 20 msec refresh rates vs. ones that have 10 msec refresh rates. > > i'd say the direct perception limit should be somewhere around 10 msec, > but there can be indirect effects that add up. (e.g. while we might not > be able to detect so small delays directly, the human eye can see > _distance_ anomalies that are caused by small delays. E.g. the feeling > of how 'smoothly' the mouse moves might be more accurate than direct > delay perception. But i'm really out on a limb here as this is so hard > to measure directly.) Quite a lot outside the computing world has been done on human perception a= nd=20 the limit of perception on what would be scheduling jitter is approximately= =20 7ms if I recall correctly. Cheers, Con --nextPart1842854.eT49bHCjT8 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQBClFjLZUg7+tp6mRURAhuHAJ0ZEVHj6l+9HOXUnuv8iEgYhxtd3QCfftK2 2URtgkMfcCxRSXzeFmJfRDQ= =opUj -----END PGP SIGNATURE----- --nextPart1842854.eT49bHCjT8-- - 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/