From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 74373 invoked by alias); 10 Nov 2016 08:34:12 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 74354 invoked by uid 89); 10 Nov 2016 08:34:11 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.7 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=State, meeting X-HELO: mail-yb0-f195.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=ZLLCrrGb7UwdTLkLQ9Yz5OlhbGBBvn9Xbft3UYAwG/w=; b=AbyDudkGdmKlc0CHb2eeS4Pv0PmdBIKRiRf0wx4bTGPRD0nPGr8RfTbYkoVjGY5OEc mey8vPRcDU0nDMmU0Dh/Cgws960zL5vhbAg0oP7vwIfy6OS+V6zdF/FKXf7rmGRKyckF ofoEWP7A2M97QiqP4kCLvw5CNsbSb3G8lNBevi+lJr3+HuC2cLfiGvI65oA47GmOqkIM ON0dukpWa3DCbbZY4vnbKISTwC0bu+2oLZVu7WlyvtM5GS1Ba54AGK3zJ7tukDvb/95/ b/E2geo1MHEBW2TAKIxSuKNGBwVIT6M7aFEV0lCKK35GEhI0nYFL+l69nDP6NeFjUIB+ ZoOA== X-Gm-Message-State: ABUngvf2jUnaOtEjKUyzxTR2aMqQObNo6iQV/08usCtVPhM0tmWKIdH97zfcMtuu0H+uSoV0I2R8ZnEHrlJH3A== X-Received: by 10.37.170.4 with SMTP id s4mr4007239ybi.144.1478766848745; Thu, 10 Nov 2016 00:34:08 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <193512EC-DC6C-4BDF-8138-1C1F54B30A12@linaro.org> From: Andrew Pinski Date: Thu, 10 Nov 2016 08:34:00 -0000 Message-ID: Subject: Re: [libc/string] State of PAGE_COPY_FWD / PAGE_COPY_THRESHOLD To: Florian Weimer Cc: Maxim Kuvyrkov , Adhemerval Zanella , GNU C Library Content-Type: text/plain; charset=UTF-8 X-SW-Source: 2016-11/txt/msg00383.txt.bz2 On Thu, Nov 10, 2016 at 12:25 AM, Florian Weimer wrote: > On 11/10/2016 09:05 AM, Andrew Pinski wrote: > >> Also memcpy/memset is useful to optimize for each micro-arch instead >> of doing this kind of optimization is better in general. I have a >> semi-optimized memcpy for ThunderX (T88, not T81 or T83; still have >> not looked into an optimized version for T83/T81 yet) and have an idea >> how to optimize it for another core but there is no way to handle this >> in glibc because of kernel or glibc infrastructure for arm64. > > > We do this all the time on x86_64 (and presumably POWER). What's missing on > Unless you want to read a file (either /proc/cpuinfo or /sys/devices/system/cpu/cpuN/regs/identification/midr_el1) the arch does not provide a way to identify what processor you are running on in userspace. There has been some discussions already on the kernel list and I was going to have another discussion with the arm folks but I can't find the email thread where the meeting was setup for :). Thanks, Andrew > > Thanks, > Florian >