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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 E0E25C10DCE for ; Thu, 12 Mar 2020 19:27:20 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C19402067C for ; Thu, 12 Mar 2020 19:27:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C19402067C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5C9FA6EB2C; Thu, 12 Mar 2020 19:27:20 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id D7B726EB2C for ; Thu, 12 Mar 2020 19:27:18 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Mar 2020 12:27:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,545,1574150400"; d="scan'208";a="243140754" Received: from adixit-mobl.amr.corp.intel.com (HELO adixit-arch.intel.com) ([10.251.157.219]) by orsmga003.jf.intel.com with ESMTP; 12 Mar 2020 12:27:17 -0700 Date: Thu, 12 Mar 2020 12:27:17 -0700 Message-ID: <87tv2twezu.wl-ashutosh.dixit@intel.com> From: "Dixit, Ashutosh" To: Umesh Nerlige Ramappa In-Reply-To: <20200303221905.25866-5-umesh.nerlige.ramappa@intel.com> References: <20200303221905.25866-1-umesh.nerlige.ramappa@intel.com> <20200303221905.25866-5-umesh.nerlige.ramappa@intel.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL/10.8 EasyPG/1.0.0 Emacs/26 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Subject: Re: [Intel-gfx] [PATCH 4/7] drm/i915/perf: add new open param to configure polling of OA buffer X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, 03 Mar 2020 14:19:02 -0800, Umesh Nerlige Ramappa wrote: > > From: Lionel Landwerlin > > This new parameter let's the application choose how often the OA > buffer should be checked on the CPU side for data availability. Longer > polling period tend to reduce CPU overhead if the application does not > care about somewhat real time data collection. > > v2: Allow disabling polling completely with 0 value (Lionel) > v3: Version the new parameter (Joonas) > v4: Rebase (Umesh) Hi Lionel, I was thinking that one way to keep things simple for now (and fix the high cpu usage issue) would be to expose _ONLY_ this OA poll period parameter to user space. That is we don't expose the interrupt or the flush ioctl to user space at this time. This way the user will be able to configure the hrtimer frequency to a lower value to bring down the cpu usage. Also we would disallow disabling the timer (and internally also not use the interrupt). So everything will happen in exactly the same way as it used to (no other changes needed) but at a lower rate if the user so chooses. What do you think about this? Thanks! -- Ashutosh _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx