From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752258AbcAIEQg (ORCPT ); Fri, 8 Jan 2016 23:16:36 -0500 Received: from mail-bn1on0056.outbound.protection.outlook.com ([157.56.110.56]:40222 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752056AbcAIEQ3 (ORCPT ); Fri, 8 Jan 2016 23:16:29 -0500 X-Greylist: delayed 889 seconds by postgrey-1.27 at vger.kernel.org; Fri, 08 Jan 2016 23:16:28 EST Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=lingzhu.xiang@mail.utoronto.ca; MIME-Version: 1.0 In-Reply-To: References: <20160106001143.GA1171@kroah.com> From: Lingzhu Xiang Date: Fri, 8 Jan 2016 23:00:54 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2] Add support for usbfs zerocopy. To: "Steinar H. 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Gunderson wrote: > Add a new interface for userspace to preallocate memory that can be > used with usbfs. This gives two primary benefits: Extended testing over one hour shows significant improved CPU usage and stability: The old CPU usage is about 12% +/- 5%. The new CPU usage is 4% +/- 1%. The setup is an i7-4600U laptop running Kinect v2 with 260MB/s isochronous and 20MB/s bulk transfers. The improvement in reducing jitter is particularly preferable to Kinect v2 driver because the isochronous data is structured and one packet lost means discarding a lot of data. Regards, Lingzhu