From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by sourceware.org (Postfix) with ESMTPS id A2CCF3951C26 for ; Tue, 22 Jun 2021 20:22:37 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A2CCF3951C26 Received: by mail-qv1-xf35.google.com with SMTP id f5so225847qvu.8 for ; Tue, 22 Jun 2021 13:22:37 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=raIH8P6EZ+y7FwksKKjyytuasJhxa+BHmrtRDxlMaJA=; b=lgOGsA4SMKklgNfxdchAuiRmumxqc2bHzDMw/2CcZ9Aq3av+aVppeqrLXhtjtQMHO8 LUO/Ik1qHrl0awZVhAKf829oxPIcgDFSAsK6HSrqdPugJpdX+EcA0g7LIHsq0txIMG+w ZrdtRhiDMG8QrPbvqDdz3zW1rpdTg6ha8z2h/1dfsD74kAk2i3E+U7rEG0LAS2Vx4bUr m4NOorsrLwDqPzTIpaFE9jQVThGh69q8zY6NTfIVKYjpFFwpwTVJTDLIuovTjaHnmmRw 8qswzWoEfpmiT5hyuvhH6+BLnu72uE0Fggv3gQlwa07A/+o0mS8T56Y9ahZH5ygQbSeO 8zXw== X-Gm-Message-State: AOAM532AToJYE5cb5Cw4Ms4OLRG3NLgkunvGYaD8XtEOcZ3UN6MySCjm v+ivnwgUZ7xOHZJdCaGNlLm9gA== X-Google-Smtp-Source: ABdhPJxyi/lybIVs/Humq7cNFOQtBcdjxFOF656OHTZLZ8cjK0y8lZEzl+QYeGFNCUBxvTuY2lgPvA== X-Received: by 2002:a0c:eb8d:: with SMTP id x13mr614199qvo.5.1624393357286; Tue, 22 Jun 2021 13:22:37 -0700 (PDT) Received: from [192.168.1.108] ([177.194.59.218]) by smtp.gmail.com with ESMTPSA id 20sm13410131qky.124.2021.06.22.13.22.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Jun 2021 13:22:36 -0700 (PDT) Subject: Re: aarch64 lacks HP_TIMING support in glibc To: Andreas Schwab Cc: Adhemerval Zanella via Libc-alpha , Andrew Pinski , Rafael Eduardo Ruviaro Christ References: <09ae1d8f-7b66-e9fc-5a98-3a002390c298@linaro.org> <87h7hpg0nb.fsf@igel.home> <87czsdfyaz.fsf@igel.home> From: Adhemerval Zanella Message-ID: <5d0500e7-363b-93c3-0d06-a47d6090dd00@linaro.org> Date: Tue, 22 Jun 2021 17:22:34 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <87czsdfyaz.fsf@igel.home> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.1 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jun 2021 20:22:38 -0000 On 22/06/2021 17:18, Andreas Schwab wrote: > On Jun 22 2021, Adhemerval Zanella wrote: > >> On 22/06/2021 16:27, Andreas Schwab wrote: >>> On Jun 22 2021, Adhemerval Zanella via Libc-alpha wrote: >>> >>>> It should be possible support hp-timing.h on aarch64 to use cntvct_el0 >>>> if the minimum supported kernel also supports it (3.2). Afaik the >>>> hp-timing will be used only for LD_DEBUG=statistics, so default usage >>>> would not be penalized. >>> >>> But then, why is it such a big deal? >> >> Do you mean support hp-timing on aarch64 or eventually trap on kernel >> on such usage? > > hp-timing in general. It helps on loader statistics, but I guess clock_gettime might be good enough. Or maybe even debug statistics are not that useful.