From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lj1-f195.google.com ([209.85.208.195]:41697 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727579AbeHIL5b (ORCPT ); Thu, 9 Aug 2018 07:57:31 -0400 From: "Matwey V. Kornilov" To: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Matwey V. Kornilov" , tfiga@chromium.org, laurent.pinchart@ideasonboard.com, matwey@sai.msu.ru, stern@rowland.harvard.edu, ezequiel@collabora.com, hdegoede@redhat.com, hverkuil@xs4all.nl, mchehab@kernel.org, rostedt@goodmis.org, mingo@redhat.com, isely@pobox.com, bhumirks@gmail.com, colin.king@canonical.com, kieran.bingham@ideasonboard.com, keiichiw@chromium.org Subject: [PATCH v3 0/2] media: usb: pwc: Don't use coherent DMA buffers for ISO transfer Date: Thu, 9 Aug 2018 12:33:05 +0300 Message-Id: <20180809093307.6001-1-matwey@sai.msu.ru> Sender: linux-media-owner@vger.kernel.org List-ID: From: "Matwey V. Kornilov" DMA cocherency slows the transfer down on systems without hardware coherent DMA. In order to demontrate this we introduce performance measurement facilities in patch 1 and fix the performance issue in patch 2 in order to obtain 4 times speedup. Changes since v2: * use dma_sync_single_for_cpu() to achive better performance * remeasured performance Changes since v1: * trace_pwc_handler_exit() call moved to proper place * detailed description added for commit 1 * additional output added to trace to track separate frames Matwey V. Kornilov (2): media: usb: pwc: Introduce TRACE_EVENTs for pwc_isoc_handler() media: usb: pwc: Don't use coherent DMA buffers for ISO transfer drivers/media/usb/pwc/pwc-if.c | 54 +++++++++++++++++++++++++++-------- include/trace/events/pwc.h | 64 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 106 insertions(+), 12 deletions(-) create mode 100644 include/trace/events/pwc.h -- 2.16.4