From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7597C04AAB for ; Tue, 7 May 2019 08:58:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2CD5204FD for ; Tue, 7 May 2019 08:58:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=renesasgroup.onmicrosoft.com header.i=@renesasgroup.onmicrosoft.com header.b="IaST4m/c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726791AbfEGI6s (ORCPT ); Tue, 7 May 2019 04:58:48 -0400 Received: from mail-eopbgr1410098.outbound.protection.outlook.com ([40.107.141.98]:34231 "EHLO JPN01-OS2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726236AbfEGI6r (ORCPT ); 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received-spf: None (protection.outlook.com: renesas.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: TyqOe9YB8l2R9L94XnNVPAKWoB8UQZO3HJ5h5Og1z2YarP5Yi6ETD2soudeVP1lKDGKhjmsaqsbmnYo7lY8l9jhdEBRCz60FWNByBFNnZU0CMEFvoLTJ2BqD0O/23Mulk9zkN95K2Yo4RCmulkSw6VgwST+ablXIVlQkBpn67sNU7aLWz19B+wf+tzCJf9tpB9EUJM5B6mxmFwV5xiuMh3qjMouOl5QTDKloLDC3M5YQaSoay99h54c5slEkz3gekzLwdsscc4SnJIuCPIOAVKcx8vfFQWt//ucr8/vmdkrF1bxUevvZQMXI3Hu4zM0prlF0tUxFDHgYkvkUujeDyUUEVfsZaseB1UUguiWZ3u/6T9wvndFr/2p4kfNovQ01KmkiFVvwLlDk60JZSBfOTlcUER5gOvwS0KA/lGncWMA= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: renesas.com X-MS-Exchange-CrossTenant-Network-Message-Id: c4ee9a9f-5d87-4180-3491-08d6d2ca3565 X-MS-Exchange-CrossTenant-originalarrivaltime: 07 May 2019 08:58:43.7703 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 53d82571-da19-47e4-9cb4-625a166a4a2a X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-Transport-CrossTenantHeadersStamped: OSBPR01MB4757 Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Wolfram-san, > From: Wolfram Sang, Sent: Friday, April 26, 2019 6:46 PM >=20 > Hi Shimoda-san, >=20 > thanks for working on this! >=20 > > Please refer to the end of this email about the performance. >=20 > Yes, nice improvements, great! Thanks! > > (I beleive if the performance is improved, the CPU load is also increas= ed.) >=20 > I do wonder about this a bit, though. IPMMU and DMA shouldn't be that > much expensive for the CPU, or? Am I overlooking something? I'm guessing that a user land app (in this case bonnie++) consumes CPU load= for some reason. I'll experiment whether my guess is correct or not by using usb 3.0 host li= ke below tomorrow: - case 1: usb 3.0 host + usb SSD as SuperSpeed (IOMMU is disabled). - case 2: usb 3.0 host + usb SSD via a usb2.0 hub as high-speed (IOMMU is = disabled). Best regards, Yoshihiro Shimoda > Kind regards, >=20 > Wolfram