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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 DC94DC64E8A for ; Mon, 30 Nov 2020 10:36:54 +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 70A1820708 for ; Mon, 30 Nov 2020 10:36:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70A1820708 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A095389CF8; Mon, 30 Nov 2020 10:36:53 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id BFD2289CF8; Mon, 30 Nov 2020 10:36:52 +0000 (UTC) IronPort-SDR: o8NpDkCZd3DzGFgWtXiJarOsV8xiIoeL3oARVmSv+xEO3yPMHbX6M2tQdujA+FLtjjtIS8SUgp ZzWtyDBwODnw== X-IronPort-AV: E=McAfee;i="6000,8403,9820"; a="160386000" X-IronPort-AV: E=Sophos;i="5.78,381,1599548400"; d="scan'208";a="160386000" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2020 02:36:50 -0800 IronPort-SDR: 3Oq2z9eo+GPn0GeAr9vThEeAk+CuRu3Eq1bMpGDJMtpwrFdNFTQqkFGiQg4r3Ca6DrbuijJSyb 9MZ8e2jGGbZA== X-IronPort-AV: E=Sophos;i="5.78,381,1599548400"; d="scan'208";a="480605490" Received: from mdubovsk-mobl1.ger.corp.intel.com (HELO [10.254.157.9]) ([10.254.157.9]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2020 02:36:48 -0800 Subject: Re: [Intel-gfx] [RFC PATCH 157/162] drm/i915: Improve accuracy of eviction stats To: Chris Wilson , Matthew Auld , intel-gfx@lists.freedesktop.org References: <20201127120718.454037-1-matthew.auld@intel.com> <20201127120718.454037-158-matthew.auld@intel.com> <160648802888.2925.2681758176898405257@build.alporthouse.com> From: Tvrtko Ursulin Organization: Intel Corporation UK Plc Message-ID: Date: Mon, 30 Nov 2020 10:36:45 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <160648802888.2925.2681758176898405257@build.alporthouse.com> Content-Language: en-US X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: dri-devel@lists.freedesktop.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 27/11/2020 14:40, Chris Wilson wrote: > Quoting Matthew Auld (2020-11-27 12:07:13) >> From: Tvrtko Ursulin >> >> Current code uses jiffie time to do the accounting and then does: >> >> diff = jiffies - start; >> msec = diff * 1000 / HZ; >> ... >> atomic_long_add(msec, &i915->time_swap_out_ms); >> >> If we assume jiffie can be as non-granular as 10ms and that the current >> accounting records all evictions faster than one jiffie as infinite speed, >> we can end up over-estimating the reported eviction throughput. >> >> Fix this by accumulating ktime_t and only dividing to more user friendly >> granularity at presentation time (debugfs read). >> >> At the same time consolidate the code a bit and convert from multiple >> atomics to single seqlock per stat. >> >> Signed-off-by: Tvrtko Ursulin >> Cc: CQ Tang >> Cc: Sudeep Dutt >> Cc: Mika Kuoppala > > A lot of effort to fix up patches after the fact, might as well make it > a real PMU interface. It did cross my mind and should be easy to add on top if deemed useful or interesting. More importantly, it is okay with me to incorporate this patch into the earlier one(s) which first added statistics. Regards, Tvrtko _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel