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_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 5C8DEC76188 for ; Tue, 16 Jul 2019 11:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E0C120880 for ; Tue, 16 Jul 2019 11:47:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GWz4yv38" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387742AbfGPLrf (ORCPT ); Tue, 16 Jul 2019 07:47:35 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:46483 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728437AbfGPLre (ORCPT ); Tue, 16 Jul 2019 07:47:34 -0400 Received: by mail-pf1-f195.google.com with SMTP id c73so8984772pfb.13; Tue, 16 Jul 2019 04:47:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:subject:to:cc:references:in-reply-to:mime-version :user-agent:message-id:content-transfer-encoding; bh=qPnqoEfs2c2FJiT2itcjWmfJK1RsKaw7z2dBi7iQTJ8=; b=GWz4yv38B5GHtENqY4vKofVQ91e0o/Wf3To5Ps1dYZG0HD5Ek2EHO2Dc7Ow7eTInF8 6V2Ylge8TO9m/bByMpQYgvAJMrZvdG3hSLoe3le3WrAf4DJkafN2xpBGM8XjRxts22Wl fwEiPyHbfrkm6UMLSuHMn/gd7z8YK8aSErG8WB+A5roIC5O0ZPZ/6GMpagTh5qiyB+K7 yG6MrQ7ON432Xy90IZVQ3KnMcyWz9iH91bIQQjqhHjYLmAxiZwGFc9kDORakmYFFow9m dvKHxsEKn/ChfEWmG3TrgmHbJEuO1ziKFvpkOF6Z/rwgSAH09LcgUIkZ09KBkugy6xrh 5rJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:subject:to:cc:references:in-reply-to :mime-version:user-agent:message-id:content-transfer-encoding; bh=qPnqoEfs2c2FJiT2itcjWmfJK1RsKaw7z2dBi7iQTJ8=; b=FYjnDJAGC0Fe1sK3mfdTuwoQu6n+wYawoYMDkkDkDTyW4gQfMOMQEPb/r+njILVWZf vGHsIc+W/T8ju1c7ZcR9J7K0smEOQKXfBuHpsa64R7TZFOph9Et6JefZkKH+HUUP0LlY QrwghaDQBKBr+DYW30XnnEYwu+d8h2JxezEDv+lp/+HYIeNs5XMDpyqqPGwaf4HvDia/ 1BH0jhBseU8mkVoJnxPPR3Bv4hHwpNIkbLXfPUxWQInmUGy1AHOseM9G2rPFBRXAH0Iz 4SssO3aB3jLXNRnBSsZA4X5D7QS47U9JebNeR4eZ98KfBuqvEXnH9QshjZEIudgnMegc QRQg== X-Gm-Message-State: APjAAAVNVv9FWeTUauqAoZB4Y2UZRN9xXgeoIvtDnUMk0VsYES4wePr/ e+643g7tgAg1qVO8NFOUXIQ= X-Google-Smtp-Source: APXvYqzHZwrzaDAsguaX2IsIyUiWc2RXpFglPckISYDzHT896XmmxWdI422IRFIGhq+LtZkupLz2ig== X-Received: by 2002:a63:60a:: with SMTP id 10mr2299610pgg.381.1563277654138; Tue, 16 Jul 2019 04:47:34 -0700 (PDT) Received: from localhost ([203.220.8.141]) by smtp.gmail.com with ESMTPSA id t10sm19804313pjr.13.2019.07.16.04.47.32 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 16 Jul 2019 04:47:33 -0700 (PDT) Date: Tue, 16 Jul 2019 21:47:27 +1000 From: Nicholas Piggin Subject: Re: [PATCH v3 0/5] Add NUMA-awareness to qspinlock To: Alex Kogan , arnd@arndb.de, bp@alien8.de, guohanjun@huawei.com, hpa@zytor.com, jglauber@marvell.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, longman@redhat.com, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, will.deacon@arm.com, x86@kernel.org Cc: daniel.m.jordan@oracle.com, dave.dice@oracle.com, rahul.x.yadav@oracle.com, steven.sistare@oracle.com References: <20190715192536.104548-1-alex.kogan@oracle.com> In-Reply-To: <20190715192536.104548-1-alex.kogan@oracle.com> MIME-Version: 1.0 User-Agent: astroid/0.14.0 (https://github.com/astroidmail/astroid) Message-Id: <1563277166.m9swqogbqb.astroid@bobo.none> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alex Kogan's on July 16, 2019 5:25 am: > Our evaluation shows that CNA also improves performance of user=20 > applications that have hot pthread mutexes. Those mutexes are=20 > blocking, and waiting threads park and unpark via the futex=20 > mechanism in the kernel. Given that kernel futex chains, which > are hashed by the mutex address, are each protected by a=20 > chain-specific spin lock, the contention on a user-mode mutex=20 > translates into contention on a kernel level spinlock.=20 What applications are those, what performance numbers? Arguably that's much more interesting than microbenchmarks (which are mainly useful to help ensure the fast paths are not impacted IMO). Thanks, Nick =