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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 51F16C76188 for ; Wed, 5 Apr 2023 16:38:22 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Ps9L442vHz3cjJ for ; Thu, 6 Apr 2023 02:38:20 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=N25+p1ID; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=intel.com (client-ip=192.55.52.93; helo=mga11.intel.com; envelope-from=dave.hansen@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=N25+p1ID; dkim-atps=neutral Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Ps9K72mMhz3bfk for ; Thu, 6 Apr 2023 02:37:26 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1680712651; x=1712248651; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=0xErBa/ZTd4QuIygEuCmz4Ddp7YfQ0AoZ3dVIG2ez3Y=; b=N25+p1IDbCy0cSYsNkhOPU7E69sETWqLDbz2s/JMbGFWU76VNmPREaAJ WxiTb2bpusbJ8EkPhtvBG399mHFH/ePJCxfRnWp0MrzwDGM5QgZsSCmdW lJx8khlSeKMwrlnGt8Ay/Wk1Y1Vn7aSEBGex1btxPfLPOt8rJzrKApw0s muRaA5KC2MOaMA0cqPJ/Fb/SXssjmLFJuR3NsSSRhqMD4LJCpA9SSeIqM Xusc1Afi9VwCVtMq56RvHCSDwG0TkC4NraRoV5uliN0Jw6uBrpweVQfaF sFYrau7lUhyatTHGBCUDjXHZ1jGyhDtO7yCIVKyG9gD9KQHOfBlMek7oq Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10671"; a="339995941" X-IronPort-AV: E=Sophos;i="5.98,321,1673942400"; d="scan'208";a="339995941" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Apr 2023 09:37:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10671"; a="932891908" X-IronPort-AV: E=Sophos;i="5.98,321,1673942400"; d="scan'208";a="932891908" Received: from kyunghyu-mobl2.amr.corp.intel.com (HELO [10.209.6.69]) ([10.209.6.69]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Apr 2023 09:37:05 -0700 Message-ID: <7360ffd2-a5aa-1373-8309-93e71ff36cbb@intel.com> Date: Wed, 5 Apr 2023 09:37:04 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.8.0 Subject: Re: [PATCH v2 0/5] locking: Introduce local{,64}_try_cmpxchg Content-Language: en-US To: Uros Bizjak , linux-alpha@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230405141710.3551-1-ubizjak@gmail.com> From: Dave Hansen In-Reply-To: <20230405141710.3551-1-ubizjak@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Ian Rogers , Peter Zijlstra , Dave Hansen , Jiaxun Yang , "H. Peter Anvin" , WANG Xuerui , Will Deacon , Jun Yi , Huacai Chen , Alexander Shishkin , Ingo Molnar , Matt Turner , Arnd Bergmann , Boqun Feng , Richard Henderson , Nicholas Piggin , Ivan Kokshaysky , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , Thomas Bogendoerfer , Jiri Olsa , Borislav Petkov Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 4/5/23 07:17, Uros Bizjak wrote: > Add generic and target specific support for local{,64}_try_cmpxchg > and wire up support for all targets that use local_t infrastructure. I feel like I'm missing some context. What are the actual end user visible effects of this series? Is there a measurable decrease in perf overhead? Why go to all this trouble for perf? Who else will use local_try_cmpxchg()? I'm all for improving things, and perf is an important user. But, if the goal here is improving performance, it would be nice to see at least a stab at quantifying the performance delta.