Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751175AbWCHVIH (ORCPT ); Wed, 8 Mar 2006 16:08:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751198AbWCHVIH (ORCPT ); Wed, 8 Mar 2006 16:08:07 -0500 Received: from threatwall.zlynx.org ([199.45.143.218]:50064 "EHLO zlynx.org") by vger.kernel.org with ESMTP id S1751175AbWCHVIF (ORCPT ); Wed, 8 Mar 2006 16:08:05 -0500 Subject: Re: [PATCH] mm: yield during swap prefetching From: Zan Lynx To: Con Kolivas Cc: =?ISO-8859-1?Q?Andr=E9?= Goddard Rosa , Lee Revell , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, ck@vds.kolivas.org In-Reply-To: References: <200603081013.44678.kernel@kolivas.org> <200603081322.02306.kernel@kolivas.org> <1141784834.767.134.camel@mindpipe> <200603081330.56548.kernel@kolivas.org> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-JnmW0dYjcbGr0gt5fDM1" Date: Wed, 08 Mar 2006 14:07:43 -0700 Message-Id: <1141852064.21958.28.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.4.2.1 X-Envelope-From: zlynx@acm.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3146 Lines: 83 --=-JnmW0dYjcbGr0gt5fDM1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Wed, 2006-03-08 at 14:05 +1100, Con Kolivas wrote: > Andr=E9 Goddard Rosa writes: >=20 > > [...] > >> > > Because being a serious desktop operating system that we are > >> > > (bwahahahaha) means the user should not have special privileges to= run > >> > > something as simple as a game. Games should not need special sched= uling > >> > > classes. We can always use 'nice' for a compile though. Real time = audio > >> > > is a completely different world to this. > > [...] > >> Well as I said in my previous reply, games should _not_ need special > >> scheduling classes. They are not written in a real time smart way and = they do > >> not have any realtime constraints or requirements. > >=20 > > Sorry Con, but I have to disagree with you on this. > >=20 > > Games are very complex software, involving heavy use of hardware resour= ces > > and they also have a lot of time constraints. So, I think they should > > use RT priorities > > if it is necessary to get the resources needed in time. >=20 > Excellent, I've opened the can of worms. >=20 > Yes, games are a in incredibly complex beast. >=20 > No they shouldn't need real time scheduling to work well if they are code= d=20 > properly. However, witness the fact that most of our games are windows=20 > ports, therefore being lower quality than the original. Witness also the=20 > fact that at last with dual core support, lots and lots (but not all) of=20 > windows games on _windows_ are having scheduling trouble and jerky playba= ck,=20 > forcing them to crappily force binding to one cpu. [snip] Games where you notice frame-rate chop because the *disk system* is using too much CPU are perfect examples of applications that should be using real-time. Multiple CPU cores and multithreading in games is another perfect example of programming that *needs* predictable real-time thread priorities. There is no other way to guarantee that physics processing takes priority over graphics updates or AI, once each task becomes separated from a monolithic main loop and spread over several CPU cores. Because games often *are* badly written, a user-friendly Linux gaming system does need a high-priority real-time task watching for a special keystroke, like C-A-Del for example, so that it can kill the other real-time tasks and return to the UI shell. Games and real-time go together like they were made for each other. --=20 Zan Lynx --=-JnmW0dYjcbGr0gt5fDM1 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.1 (GNU/Linux) iD8DBQBED0efG8fHaOLTWwgRApodAJ9COGrzAcml6M/evrUrk7clMIU9+wCfZF0S ALgGVbBcrrwS5nRPhSdtdEk= =s+zF -----END PGP SIGNATURE----- --=-JnmW0dYjcbGr0gt5fDM1-- - 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/