From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] shrink per_cpu_pages to fit 32byte cacheline From: Arjan van de Ven Reply-To: arjanv@redhat.com In-Reply-To: <20040913233835.GA23894@logos.cnet> References: <20040913233835.GA23894@logos.cnet> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-pezfflIUTYShj6qFhiWu" Message-Id: <1095142204.2698.12.camel@laptop.fenrus.com> Mime-Version: 1.0 Date: Tue, 14 Sep 2004 08:10:04 +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: Marcelo Tosatti Cc: akpm@osdl.org, "Martin J. Bligh" , linux-mm@kvack.org List-ID: --=-pezfflIUTYShj6qFhiWu Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2004-09-14 at 01:38, Marcelo Tosatti wrote: > Subject says it all, the following patch shrinks per_cpu_pages > struct from 24 to 16bytes, that makes the per CPU array containing > hot and cold "per_cpu_pages[2]" fit on 32byte cacheline. This structure > is often used so I bet this is a useful optimization. I'm not sure it's worth it. cachelines are 64 or 128 bytes nowadays and a short access costs you at least 1 extra cycle per access on several x86 cpus (byte and dword are cheap, short is not) --=-pezfflIUTYShj6qFhiWu Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQBBRos8xULwo51rQBIRApRBAKCEQI6ROdhtuEwET+va5dyPCnG33gCgjniy Bzn+uGxkiCB00vvDIo+/0Ag= =v/O0 -----END PGP SIGNATURE----- --=-pezfflIUTYShj6qFhiWu-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org