From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sm.strop.com.pl (sm.strop.com.pl [83.17.179.219]) by sourceware.org (Postfix) with ESMTPS id 336553858D28 for ; Mon, 3 Jul 2023 17:35:13 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 336553858D28 Authentication-Results: sourceware.org; dmarc=pass (p=reject dis=none) header.from=ztk-rp.eu Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=ztk-rp.eu Received: from zorro.ztk-rp.eu ([::ffff:10.208.4.171]) (TLS: TLS1.2,256bits,ECDHE_RSA_AES_256_GCM_SHA384) by sm.strop.com.pl with ESMTPS; Mon, 03 Jul 2023 19:34:46 +0200 id 0000000018A9AC73.0000000064A306B6.0000117A Received: from public-gprs569267.centertel.pl ([37.225.86.244]:7150 helo=[192.168.43.32]) by zorro.ztk-rp.eu with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1qGNRk-00E8h5-J9; Mon, 03 Jul 2023 19:34:45 +0200 Message-ID: <53154623-01fc-62e6-fe25-9f164b67e6e3@ztk-rp.eu> Date: Mon, 3 Jul 2023 19:34:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Content-Language: en-US To: "Richard Earnshaw (lists)" , Ian Lance Taylor Cc: Martin Uecker , "gcc@gcc.gnu.org" References: <439affd4-11fe-de80-94c8-6fc64cbf76ec@ztk-rp.eu> <112e711791835d56cca38654f83a009cb46707d4.camel@gwdg.de> <940e9ae5-8649-5a28-e29f-06f0b2982892@ztk-rp.eu> <33c6c1a6-ca51-bf57-fdcd-d62b738a6f99@arm.com> From: =?UTF-8?Q?Rafa=c5=82_Pietrak?= In-Reply-To: <33c6c1a6-ca51-bf57-fdcd-d62b738a6f99@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 37.225.86.244 X-SA-Exim-Mail-From: embedded@ztk-rp.eu X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,KAM_DMARC_STATUS,NICE_REPLY_A,SPF_PASS,TXREP,T_SCC_BODY_TEXT_LINE,T_SPF_HELO_PERMERROR autolearn=ham autolearn_force=no version=3.4.6 Subject: Re: wishlist: support for shorter pointers X-SA-Exim-Version: 4.2.1 (built Sat, 13 Feb 2021 17:57:42 +0000) X-SA-Exim-Scanned: Yes (on zorro.ztk-rp.eu) Received-SPF: unknown (IP address lookup failed.) SPF=FROM; sender=embedded@ztk-rp.eu; remoteip=::ffff:10.208.4.171; remotehost=; helo=zorro.ztk-rp.eu; receiver=sm.strop.com.pl; List-Id: W dniu 3.07.2023 o 18:57, Richard Earnshaw (lists) pisze: > On 03/07/2023 17:42, Rafał Pietrak via Gcc wrote: >> Hi Ian, [---------] >> And WiKi reporting up to 40% performance improvements in some corner >> cases is impressive and encouraging. I believe, that the reported >> average of 5-8% improvement would be significantly better within MCU >> tiny resources environment. In MCU world, such improvement could mean >> fit-nofit of a project into a particular device. >> >> -R > > I think you need to be very careful when reading benchmarketing (sic) > numbers like this.  Firstly, this is a 32-bit vs 64-bit measurement; > secondly, the benchmark (spec 2000) is very old now and IIRC was not > fully optimized for 64-bit processors (it predates the 64-bit version of > the x86 instruction set); thirdly, there are benchmarks in SPEC which > are very sensitive to cache size and the 32-bit ABI just happened to > allow them to fit enough data in the caches to make the numbers leap. Yes. Sure. I am. I thought I've expressed it clearly, that the "fantastic 40%" I regard as just "corner case" - those don't usually reflect ordinary usage. I was only highlighting the fact, that mare 5-8% improvement can result on fit-nofit of a particular design into a particular device ... in consequence requiring to use 4k-RAM device instead of 2k-RAM one. Tiny improvements of performance of x64 workhorses can become relatively huge in micros like stm32. That's all. -R