Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752824AbcDZVfe (ORCPT ); Tue, 26 Apr 2016 17:35:34 -0400 Received: from sauhun.de ([89.238.76.85]:52482 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736AbcDZVfb (ORCPT ); Tue, 26 Apr 2016 17:35:31 -0400 Date: Tue, 26 Apr 2016 23:35:27 +0200 From: Wolfram Sang To: Dirk Behme Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Oleksij Rempel Subject: Re: [PATCH] i2c: imx: use usleep_range(50,100) instead of udelay(50) Message-ID: <20160426213527.GI4587@katana> References: <1461652066-16456-1-git-send-email-dirk.behme@de.bosch.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="nO3oAMapP4dBpMZi" Content-Disposition: inline In-Reply-To: <1461652066-16456-1-git-send-email-dirk.behme@de.bosch.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1886 Lines: 52 --nO3oAMapP4dBpMZi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 26, 2016 at 08:27:46AM +0200, Dirk Behme wrote: > From: Oleksij Rempel >=20 > Documentation/timers/timers-howto.txt recommends to use > usleep_range on delays > 10usec. According to my test results > with Neonode zForce touchscreen driver, usleep_range indeed > reduces CPU load. >=20 > Stats collected with "./perf record -a -g -F 1000 sleep 10" >=20 > i2c-imx with udelay(50): > 34.19% 0.00% irq/220-Neonode [kernel.kallsyms] [k] irq_thread > ---irq_thread > |--33.75%--irq_thread_fn > | |--19.27%--0x7f08a878 > | | i2c_master_recv > | | i2c_transfer > | | __i2c_transfer > | | i2c_imx_xfer > | | |--11.71%--i2c_imx_trx_complete Reworded $subject to match code and applied to for-next, thanks! --nO3oAMapP4dBpMZi Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXH98fAAoJEBQN5MwUoCm2+iEP/1xpIa7d1OBm/dbm3MkgTr6j d5bCX9fSQ50CKuKQWXs1zx1rhUuPfL1M1vTgxZDzHmRxUGooD0grBc6LrCxDp2AR IAyFhvPKXiRpY5UYlagFMi0SaPTnlHdAQ5Uo+1ADOypq5CD+4AgHlQC4ZxLweKi7 WJ5rBqfpeS6khTjB3LjFNOZbA+x1E6Xr0ssn73bCE6gCWMDdeUYk0izX4isd8f2G ztAEfprLZ5umezRwQ3HB043xFpfcQB0aLGNHWKkbiOODWODDPzdqIagMFJirPT79 oIPpMZAYwDKhzuTq+wNlEU44CCp7HLuYXucLuCx80yWBXud2b3C3lWpF84VsSCmA h0tVscdfeYesNpGOl1EvFxrptIMLTKGZgloFFvjNJ5JwW9H5UB28lcnrJ/9xo+yX QnX3NlfJM/e+6KNnS/ulObcy5Wu44KMUa0Zm9zWJSV1wZQkRFNo5EjhexDYyOH9j IRAjnXUr5o5P7JMuN/AD7SEeBTn2xS773oaVmMoRza/T1bmcroXMb/opqzxtrLdh vigqkUijUqjSTVOhPTX04wr4SxoYKBnr4QYQMOjxZCSIRIcb3GS+4inAlbNBT3ww 1EFmcxucrZAIX0LClerb/zBLJns9AbB5576QiAwnpE9Y7cUsA7a6HunSQIc7BENx bnEbkTIOc+TQ2Uh/DQtO =vm/Y -----END PGP SIGNATURE----- --nO3oAMapP4dBpMZi--