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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C58A3C433F5 for ; Thu, 17 Feb 2022 15:54:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1BFC110EADE; Thu, 17 Feb 2022 15:54:04 +0000 (UTC) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by gabe.freedesktop.org (Postfix) with ESMTPS id A85CC10EADE; Thu, 17 Feb 2022 15:54:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1645113243; x=1676649243; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=feiIE8hKQ7xOTurPToJ7wkzWqz3KqfWns/T191tEu1c=; b=Qbs6jasBXbBQ/AIf7r6cv9n+A72a2rCHeGHSAUhUrw5BjJil3WTfS9sL M5rt4P7ALCE5CcyFuzY9MAFyUsqAUvWRkLWgEw1L5HrEsJ7hROrnWz3lA N2KBHa5TWKACX+3eISdD3UeZwcA/ca88WlcCxAT3I8eZwsJahJ8fixd/n w5hpNmcGMU4VCFxY2RVm+IVVg8G492KZR5ktPqLxrQSEz8qxB/OUUE2QE tsz9oWznnTfKcpun/U3ehxghGRPRXlElI20vsdbacbNnyZSRDfl1SP7sP TtPBAINxx/cicponjiEkn3gqbbcznEwLmiN1OT9RwAiPjNvSFz7hKRtXo A==; X-IronPort-AV: E=McAfee;i="6200,9189,10261"; a="249737135" X-IronPort-AV: E=Sophos;i="5.88,376,1635231600"; d="scan'208";a="249737135" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2022 07:54:03 -0800 X-IronPort-AV: E=Sophos;i="5.88,376,1635231600"; d="scan'208";a="545672799" Received: from pkivi-mobl.ger.corp.intel.com (HELO intel.com) ([10.252.43.228]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2022 07:54:00 -0800 Date: Thu, 17 Feb 2022 16:53:58 +0100 From: Andi Shyti To: Tvrtko Ursulin Message-ID: References: <20220217144158.21555-1-andi.shyti@linux.intel.com> <20220217144158.21555-6-andi.shyti@linux.intel.com> <12c2fcf8-ef3b-e59c-fe1e-23bc8f12cfe5@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <12c2fcf8-ef3b-e59c-fe1e-23bc8f12cfe5@linux.intel.com> Subject: Re: [Intel-gfx] [PATCH v5 5/7] drm/i915/gt: Create per-tile RC6 sysfs interface 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 , Lucas De Marchi , DRI Devel , Chris Wilson , Matthew Auld Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Hi Tvrtko, > > Now tiles have their own sysfs interfaces under the gt/ > > directory. Because RC6 is a property that can be configured on a > > tile basis, then each tile should have its own interface > > > > The new sysfs structure will have a similar layout for the 4 tile > > case: > > > > /sys/.../card0 > > ├── gt > > │   ├── gt0 > > │   │   ├── id > > │   │   ├── rc6_enable > > │   │   ├── rc6_residency_ms > > . . . > > . . . > > . . > > │   └── gtN > > │   ├── id > > │   ├── rc6_enable > > │   ├── rc6_residency_ms > > │ . > > │ . > > │ > > └── power/ -+ > > ├── rc6_enable | Original interface > > ├── rc6_residency_ms +-> kept as existing ABI; > > . | it multiplexes over > > . | the GTs > > -+ > > > > The existing interfaces have been kept in their original location > > to preserve the existing ABI. They act on all the GTs: when > > reading they provide the average value from all the GTs. > > Average feels very odd to me. I'd ask if we can get away providing an errno > instead? Or tile zero data? Real multiplexing would be providing something when reading and when writing. The idea of average came while revieweing with Chris the write multiplexing. Indeed it makes sense to provide some common value, but I don't know how useful it can be to the user (still if the user needs any average). Joonas, Chris... any idea? > Case in point, and please correct me if I am wrong, legacy rc6_enable > returns tile zero, while residency returns average. As the interface is done now, the rc6_enable is just returning whether the gpu (i.e. i915, not gt) supports RC6 or not. I think there is a patch later. > Even the deprecated message gets logged with every access right? > > Btw is the deperecated message limited to multi-tile platforms (can't see > that it is) and what is the plan for that? yes, at this point the message would need to be removed and I forgot to do it. > It's a tough problem, no easy answers even after all this time. :D yeah! quite hard to get it conceptually right! Thanks Tvrtko, Andi