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=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 9A730C3F2D1 for ; Wed, 4 Mar 2020 05:48:28 +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 77C4F214D8 for ; Wed, 4 Mar 2020 05:48:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77C4F214D8 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 2952A6EAAC; Wed, 4 Mar 2020 05:48:28 +0000 (UTC) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by gabe.freedesktop.org (Postfix) with ESMTPS id DDE2F6EAAC for ; Wed, 4 Mar 2020 05:48:26 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2020 21:48:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,513,1574150400"; d="scan'208";a="440881445" Received: from adixit-mobl.amr.corp.intel.com (HELO adixit-arch.intel.com) ([10.251.157.237]) by fmsmga006.fm.intel.com with ESMTP; 03 Mar 2020 21:48:26 -0800 Date: Tue, 03 Mar 2020 21:48:25 -0800 Message-ID: <87v9nku0uu.wl-ashutosh.dixit@intel.com> From: "Dixit, Ashutosh" To: Umesh Nerlige Ramappa In-Reply-To: <20200303221905.25866-8-umesh.nerlige.ramappa@intel.com> References: <20200303221905.25866-1-umesh.nerlige.ramappa@intel.com> <20200303221905.25866-8-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 7/7] drm/i915/perf: add flushing ioctl 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 14:19:05 -0800, Umesh Nerlige Ramappa wrote: > > From: Lionel Landwerlin > > With the currently available parameters for the i915-perf stream, > there are still situations that are not well covered : > > If an application opens the stream with polling disable or at very low > frequency and OA interrupt enabled, no data will be available even > though somewhere between nothing and half of the OA buffer worth of > data might have landed in memory. > > To solve this issue we have a new flush ioctl on the perf stream that > forces the i915-perf driver to look at the state of the buffer when > called and makes any data available through both poll() & read() type > syscalls. > > v2: Version the ioctl (Joonas) > v3: Rebase (Umesh) > > Signed-off-by: Lionel Landwerlin > Signed-off-by: Umesh Nerlige Ramappa [snip] > +/** > + * i915_perf_flush_data - handle `I915_PERF_IOCTL_FLUSH_DATA` ioctl > + * @stream: An enabled i915 perf stream > + * > + * The intention is to flush all the data available for reading from the OA > + * buffer > + */ > +static void i915_perf_flush_data(struct i915_perf_stream *stream) > +{ > + stream->pollin = oa_buffer_check(stream, true); > +} Since this function doesn't actually wake up any thread (which anyway can be done by sending a signal to the blocked thread), is the only purpose of this function to update OA buffer head/tail? But in that it is not clear why a separate ioctl should be created for this, can't the read() call itself call oa_buffer_check() to update the OA buffer head/tail? Again just trying to minimize uapi changes if possible. _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx