Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756521AbYBRRf1 (ORCPT ); Mon, 18 Feb 2008 12:35:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751889AbYBRRfL (ORCPT ); Mon, 18 Feb 2008 12:35:11 -0500 Received: from turing-police.cc.vt.edu ([128.173.14.107]:45161 "EHLO turing-police.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751754AbYBRRfK (ORCPT ); Mon, 18 Feb 2008 12:35:10 -0500 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: "Zhang, Yanmin" Cc: David Miller , dada1@cosmosbay.com, herbert@gondor.apana.org.au, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: tbench regression in 2.6.25-rc1 In-Reply-To: Your message of "Mon, 18 Feb 2008 16:12:38 +0800." <1203322358.3027.200.camel@ymzhang> From: Valdis.Kletnieks@vt.edu References: <47B52B95.3070607@cosmosbay.com> <1203057044.3027.134.camel@ymzhang> <47B59FFC.4030603@cosmosbay.com> <20080215.152200.145584182.davem@davemloft.net> <1203322358.3027.200.camel@ymzhang> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1203356033_2991P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Mon, 18 Feb 2008 12:33:53 -0500 Message-ID: <20040.1203356033@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1251 Lines: 35 --==_Exmh_1203356033_2991P Content-Type: text/plain; charset=us-ascii On Mon, 18 Feb 2008 16:12:38 +0800, "Zhang, Yanmin" said: > I also think __refcnt is the key. I did a new testing by adding 2 unsigned long > pading before lastuse, so the 3 members are moved to next cache line. The performance is > recovered. > > How about below patch? Almost all performance is recovered with the new patch. > > Signed-off-by: Zhang Yanmin Could you add a comment someplace that says "refcnt wants to be on a different cache line from input/output/ops or performance tanks badly", to warn some future kernel hacker who starts adding new fields to the structure? --==_Exmh_1203356033_2991P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFHucGBcC3lWbTT17ARAuBuAJoC9jm6ztQBAPBUryQDldMiNtKl4wCdF3r+ PnOci+BHj3mVt3k/X5tU/3A= =6j9Z -----END PGP SIGNATURE----- --==_Exmh_1203356033_2991P-- -- 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/