From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philip Balister Subject: Change in mmap driver performance from 2..6.38 to 2.6.39 Date: Mon, 11 Jul 2011 10:21:49 -0400 Message-ID: <4E1B06FD.5090107@balister.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail.geekisp.com ([216.168.135.169]:32768 "EHLO starfish.geekisp.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753997Ab1GKO2c (ORCPT ); Mon, 11 Jul 2011 10:28:32 -0400 Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "linux-omap@vger.kernel.org" I have a device drier that uses a mmap'd section of memory to expose dma buffers to user space. (https://github.com/balister/linux-omap-philip/blob/e100-2.6.38/drivers/misc/usrp_e.c). I have it running on the 2.6.38 and 2.6.39 kernel, but it looks like read performance is much slower in the .39 version than the .28 version. Does anyone know what changed between these two kernel versions and how it might fix it? Thanks, Philip