Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753822AbbLRIXg (ORCPT ); Fri, 18 Dec 2015 03:23:36 -0500 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:40627 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468AbbLRIXf (ORCPT ); Fri, 18 Dec 2015 03:23:35 -0500 Date: Fri, 18 Dec 2015 08:23:21 +0000 From: Mark Brown To: Xiubo Li Cc: linux-kernel@vger.kernel.org Message-ID: <20151218082321.GW5727@sirena.org.uk> References: <1450077274-25942-1-git-send-email-lixiubo@cmss.chinamobile.com> <20151214175756.GW5727@sirena.org.uk> <566FD138.4010601@cmss.chinamobile.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="YOs9+ySvlQ/qtugP" Content-Disposition: inline In-Reply-To: <566FD138.4010601@cmss.chinamobile.com> X-Cookie: revolutionary, adj.: User-Agent: Mutt/1.5.24 (2015-08-30) X-SA-Exim-Connect-IP: 94.175.94.161 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH] regmap: flat: introduce register striding to save somememories X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1977 Lines: 57 --YOs9+ySvlQ/qtugP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Dec 15, 2015 at 04:37:12PM +0800, Xiubo Li wrote: > On 15/12/2015 01:57, Mark Brown wrote: > >On Mon, Dec 14, 2015 at 03:14:34PM +0800, Xiubo Li wrote: > >I'm guessing for your particular register maps the performance isn't too > >big an issue... do you have any numbers for how much space you're > >saving overall? > Not yet, but maybe in the future we could see a larger register > striding, like 32 for MMIO using flat cache. OK, well I'd like to se=20 > >Is it worth finding a way to make this possible to > >enable on maps that benefit? > I'm thinking to use the bit rotation to improve the performance of > the whole regmap. > like: > if(reg % reg_stride) --> if(!IS_ALIGNED(reg, reg_stride)) > ... > index =3D reg / reg_stride; --> index =3D reg >> reg_stride_order; >=20 > And do you have any comment and suggestion for the above? I think we'll need to continue supporting non power of two strides so an unconditional conversion to shifts might be an issue - some weird DSP probably does that. --YOs9+ySvlQ/qtugP Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJWc8J4AAoJECTWi3JdVIfQClwH/0j9sUvZfS0zuVWDqUUtJE65 /gNYfpjtLpx16diUnOxkSA2qJzITgqySFu13fmVOyFqFt0+Gy8zUnVw6miseSU9P bGRGibnynn6hZNDCWstn599v5MlSjEi8Lfi/GCQ7V6goKPFay7mVj+NoN+tQQVAJ 6AKZCyELRSi1qvE30WxO2qXvsLXqxz0sOaTVxQKCQtZlVh7/C+zglGbYiHBmIvZo gNpVFaqvDSLn5Q8UX1aEGMZlkle3YiL8TI0mGSXy224unV6l1PzaUBe/YVzRonXY JCXeVuYBlT+kcwoUXWjgYSZ/1MfVViEGZsWYcRRz+8/KLl/+SIlEGhN+va9cVtg= =gSCM -----END PGP SIGNATURE----- --YOs9+ySvlQ/qtugP-- -- 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/