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 X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9A71C33CAF for ; Thu, 16 Jan 2020 20:20:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7FF3B206D9 for ; Thu, 16 Jan 2020 20:20:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579206006; bh=oko1vr6NZIkbqblBi6ADclwFu8hYoUF6zOgs+mmCjwY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=efmBtKw9Tl0PrICe+EkNirqrZqXkQwslukxBSLs0fzaskSHI0vy9uxY7FQFVjtN6m mBnY2NTHXbpNcKvhUAb2eMfmOSjaAMQS3rFhsJWdMiOwoToAnUqqO/Uv+NuO0oUeH+ UDLMsY5Ybqfuzx1iQSsFWUVIXgxscIf8LZAAYM5A= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733244AbgAPUUF (ORCPT ); Thu, 16 Jan 2020 15:20:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:38550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727022AbgAPUUF (ORCPT ); Thu, 16 Jan 2020 15:20:05 -0500 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0AB0C2081E for ; Thu, 16 Jan 2020 20:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579206004; bh=oko1vr6NZIkbqblBi6ADclwFu8hYoUF6zOgs+mmCjwY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=L+rMfwJVUI9W+d2CoFvavrawmV6XxbnS/C5pFOW3GNaz/dDJWJPZM8duGoLOAL4lG Z02NHO/8MGKmfFb7GIu6L6UBs5VQJuL2gCzfJtQIf5HIZsqZ0+yd6MnHhIphnFuyoZ f3RLMs/ybk1B0MMAwdTLCraQ7qACz4TRbZO2ykR0= Received: by mail-wm1-f42.google.com with SMTP id q9so5124735wmj.5 for ; Thu, 16 Jan 2020 12:20:03 -0800 (PST) X-Gm-Message-State: APjAAAXIOeAdWHYffJJKftFocKyW3tv5jiwtrT9dxnVnxyQyfIPFKGj6 NQ3NF6GUufaPVfm8qb1H/soLO2pPPelGu7YaPzUaGA== X-Google-Smtp-Source: APXvYqy/LKhOLCc4c+qZpvX/KQlnVohcy3HlKPdTJR43s7e+TgAW2p8Y+rne7KnqV+o60SXTwTHEOrPWPUde8RosJLE= X-Received: by 2002:a05:600c:20c7:: with SMTP id y7mr794016wmm.21.1579206002474; Thu, 16 Jan 2020 12:20:02 -0800 (PST) MIME-Version: 1.0 References: <1b278bc1f6859d4df734fb2cde61cf298e6e07fd.1579196675.git.christophe.leroy@c-s.fr> <874kwvf9by.fsf@nanos.tec.linutronix.de> In-Reply-To: <874kwvf9by.fsf@nanos.tec.linutronix.de> From: Andy Lutomirski Date: Thu, 16 Jan 2020 12:19:50 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH v4 08/11] lib: vdso: allow fixed clock mode To: Thomas Gleixner Cc: Christophe Leroy , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , nathanl@linux.ibm.com, Arnd Bergmann , Vincenzo Frascino , Andrew Lutomirski , LKML , linuxppc-dev , linux-arm-kernel , "open list:MIPS" , X86 ML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 16, 2020 at 12:14 PM Thomas Gleixner wrote: > > Christophe Leroy writes: > > Can you please adjust the prefix for future patches to lib/vdso: and > start the sentence after the colon with an uppercase letter? > > > On arches like POWERPC, the clock is always the timebase, it > > Please spell out architectures. Changelogs are not space constraint. > > > cannot be changed on the fly and it is always VDSO capable. > > Also this sentence does not make sense as it might suggests that > architectures with a fixed compile time known clocksource have something > named timebase. Something like this is more clear: > > Some architectures have a fixed clocksource which is known at compile > time and cannot be replaced or disabled at runtime, e.g. timebase on > PowerPC. For such cases the clock mode check in the VDSO code is > pointless. > I wonder if we should use this on x86 bare-metal if we have sufficiently invariant TSC. (Via static_cpu_has(), not compiled in.) Maybe there is no such x86 machine. I really really want Intel or AMD to introduce machines where the TSC pinky-swears to count in actual nanoseconds. --Andy 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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8B479C33CAF for ; Thu, 16 Jan 2020 21:21:19 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3813320728 for ; Thu, 16 Jan 2020 21:21:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="L+rMfwJV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3813320728 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47zHDq5SpqzDr5Z for ; Fri, 17 Jan 2020 08:21:15 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=luto@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=L+rMfwJV; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (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 47zFtJ4s9JzDqmC for ; Fri, 17 Jan 2020 07:20:07 +1100 (AEDT) Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0364D2077C for ; Thu, 16 Jan 2020 20:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579206004; bh=oko1vr6NZIkbqblBi6ADclwFu8hYoUF6zOgs+mmCjwY=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=L+rMfwJVUI9W+d2CoFvavrawmV6XxbnS/C5pFOW3GNaz/dDJWJPZM8duGoLOAL4lG Z02NHO/8MGKmfFb7GIu6L6UBs5VQJuL2gCzfJtQIf5HIZsqZ0+yd6MnHhIphnFuyoZ f3RLMs/ybk1B0MMAwdTLCraQ7qACz4TRbZO2ykR0= Received: by mail-wm1-f46.google.com with SMTP id p9so5148698wmc.2 for ; Thu, 16 Jan 2020 12:20:03 -0800 (PST) X-Gm-Message-State: APjAAAXMluc1HgnL8mRprcQqCkTS8jJUed9KlGR9vI7LpR5qQJGKSjmE t0/t786efgF0LVEpeaDDHKs3GoiSFVFVYA1vImK2aA== X-Google-Smtp-Source: APXvYqy/LKhOLCc4c+qZpvX/KQlnVohcy3HlKPdTJR43s7e+TgAW2p8Y+rne7KnqV+o60SXTwTHEOrPWPUde8RosJLE= X-Received: by 2002:a05:600c:20c7:: with SMTP id y7mr794016wmm.21.1579206002474; Thu, 16 Jan 2020 12:20:02 -0800 (PST) MIME-Version: 1.0 References: <1b278bc1f6859d4df734fb2cde61cf298e6e07fd.1579196675.git.christophe.leroy@c-s.fr> <874kwvf9by.fsf@nanos.tec.linutronix.de> In-Reply-To: <874kwvf9by.fsf@nanos.tec.linutronix.de> From: Andy Lutomirski Date: Thu, 16 Jan 2020 12:19:50 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH v4 08/11] lib: vdso: allow fixed clock mode To: Thomas Gleixner Content-Type: text/plain; charset="UTF-8" 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: nathanl@linux.ibm.com, Arnd Bergmann , X86 ML , LKML , "open list:MIPS" , Paul Mackerras , Andrew Lutomirski , Vincenzo Frascino , linuxppc-dev , linux-arm-kernel Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Jan 16, 2020 at 12:14 PM Thomas Gleixner wrote: > > Christophe Leroy writes: > > Can you please adjust the prefix for future patches to lib/vdso: and > start the sentence after the colon with an uppercase letter? > > > On arches like POWERPC, the clock is always the timebase, it > > Please spell out architectures. Changelogs are not space constraint. > > > cannot be changed on the fly and it is always VDSO capable. > > Also this sentence does not make sense as it might suggests that > architectures with a fixed compile time known clocksource have something > named timebase. Something like this is more clear: > > Some architectures have a fixed clocksource which is known at compile > time and cannot be replaced or disabled at runtime, e.g. timebase on > PowerPC. For such cases the clock mode check in the VDSO code is > pointless. > I wonder if we should use this on x86 bare-metal if we have sufficiently invariant TSC. (Via static_cpu_has(), not compiled in.) Maybe there is no such x86 machine. I really really want Intel or AMD to introduce machines where the TSC pinky-swears to count in actual nanoseconds. --Andy 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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25614C33CAF for ; Thu, 16 Jan 2020 20:20:08 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E92AD2077B for ; Thu, 16 Jan 2020 20:20:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OfETu3Mt"; 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Thu, 16 Jan 2020 12:20:04 -0800 (PST) X-Gm-Message-State: APjAAAVbnbc0jtFdowSCGH6+Rm/2TtMAfcBDrAn84PFj9gih6oI8Pb1+ AYu9eMx9lsfCIiYDaZoyKGvjf80o6b5XQwmc2oL2hA== X-Google-Smtp-Source: APXvYqy/LKhOLCc4c+qZpvX/KQlnVohcy3HlKPdTJR43s7e+TgAW2p8Y+rne7KnqV+o60SXTwTHEOrPWPUde8RosJLE= X-Received: by 2002:a05:600c:20c7:: with SMTP id y7mr794016wmm.21.1579206002474; Thu, 16 Jan 2020 12:20:02 -0800 (PST) MIME-Version: 1.0 References: <1b278bc1f6859d4df734fb2cde61cf298e6e07fd.1579196675.git.christophe.leroy@c-s.fr> <874kwvf9by.fsf@nanos.tec.linutronix.de> In-Reply-To: <874kwvf9by.fsf@nanos.tec.linutronix.de> From: Andy Lutomirski Date: Thu, 16 Jan 2020 12:19:50 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH v4 08/11] lib: vdso: allow fixed clock mode To: Thomas Gleixner X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200116_122004_818915_D0B5A4A6 X-CRM114-Status: GOOD ( 15.37 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Christophe Leroy , nathanl@linux.ibm.com, Arnd Bergmann , Benjamin Herrenschmidt , X86 ML , LKML , "open list:MIPS" , Paul Mackerras , Andrew Lutomirski , Michael Ellerman , Vincenzo Frascino , linuxppc-dev , linux-arm-kernel Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jan 16, 2020 at 12:14 PM Thomas Gleixner wrote: > > Christophe Leroy writes: > > Can you please adjust the prefix for future patches to lib/vdso: and > start the sentence after the colon with an uppercase letter? > > > On arches like POWERPC, the clock is always the timebase, it > > Please spell out architectures. Changelogs are not space constraint. > > > cannot be changed on the fly and it is always VDSO capable. > > Also this sentence does not make sense as it might suggests that > architectures with a fixed compile time known clocksource have something > named timebase. Something like this is more clear: > > Some architectures have a fixed clocksource which is known at compile > time and cannot be replaced or disabled at runtime, e.g. timebase on > PowerPC. For such cases the clock mode check in the VDSO code is > pointless. > I wonder if we should use this on x86 bare-metal if we have sufficiently invariant TSC. (Via static_cpu_has(), not compiled in.) Maybe there is no such x86 machine. I really really want Intel or AMD to introduce machines where the TSC pinky-swears to count in actual nanoseconds. --Andy _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel