From owner-dev-commits-src-all@freebsd.org Mon Aug 2 03:47:38 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 8C6E566BA04; Mon, 2 Aug 2021 03:47:38 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-qk1-x72a.google.com (mail-qk1-x72a.google.com [IPv6:2607:f8b0:4864:20::72a]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4GdP8p3Fr2z4hXH; Mon, 2 Aug 2021 03:47:38 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: by mail-qk1-x72a.google.com with SMTP id t66so15520909qkb.0; Sun, 01 Aug 2021 20:47:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=4CjCuYTuuhunBpUawLkExsoHRoGyxR7zBr3lQgIslSY=; b=mWNHyeBWIe/uYrW6tmZYHwz9334sf9oc93xosmdpiYo1nYBg5SgTmYJyD7kd72RiGS eOxiZNbtoASVkd9wrFRVr6Qm1KcO+EnJXK44nbNdStaa6T27QTOHHDHpv2dU/yih5Hno g0fFNfH1uduGgfNf63UmJdkp1JMqcVSdomrw1oKu/23HBd1H7ltrbYr4QtFJFm3Kwrpw q2pG+SH1KoruBUalK+zAWl5B4MjnDoekwct6MiIUAUrLGSZOzMSWIvz8jwO2dH3K9+IK 6Kp0wfcXUX82W2+108AQMQfDL8U6TDa/v7FRS7SruaLYqsfCkQnkkdviUCLu3c06EK0c d+kg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4CjCuYTuuhunBpUawLkExsoHRoGyxR7zBr3lQgIslSY=; b=Qc8uBS+rH7sYqEkhRUmp7Eg7QHfd2Q8WcQT5AQ1CyULhk39D2VviOLnUAfGq+mYzhQ echFaFzv9GO+MFa/c/QnrSZbiZFKcuthNAsgC/k2b3xA0imJdVvxIgKPLQB4ALp00GHc 4Tu+k8xGFP5CauTemiKKT6t0mJqUpBApxSKbxULOu2an1MNDYCHjE0s5KGGxsvz8B5EI YcQSVeXvmIQxIlIzC6ILwRr2Z3i4+9ZyA9vxa22beE5R0F62gG+fPdf09yKnuSgk3m7C by4kh54VlohazSKNRBSynvcTYbDjtyq5F/WhLPjH8vFkIwKDPqmbHE7UpYDVns70gFFg 94qA== X-Gm-Message-State: AOAM531z7HM29f96NehbNAjBsVecBPjpdwtKt+TwuWDLeChQ9teUX/ij 8tf1ggZg7Li2ylHjl+olJeCclhRu8Qg= X-Google-Smtp-Source: ABdhPJyO7zYu3m0b7y88H5rllandvCRWpCy1lfZO405k0oMRHbkQC55eo9DKVD80VV6E6amQeCwCWg== X-Received: by 2002:a37:bca:: with SMTP id 193mr14100255qkl.120.1627876057211; Sun, 01 Aug 2021 20:47:37 -0700 (PDT) Received: from spectre.mavhome.dp.ua (104-55-12-234.lightspeed.knvltn.sbcglobal.net. [104.55.12.234]) by smtp.gmail.com with ESMTPSA id w5sm4061675qtv.3.2021.08.01.20.47.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 01 Aug 2021 20:47:36 -0700 (PDT) Sender: Alexander Motin Subject: Re: git: 8bb173fb5bc3 - main - sched_ule(4): Use trylock when stealing load. To: Mateusz Guzik Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org References: <202108020258.1722walG094152@gitrepo.freebsd.org> From: Alexander Motin Message-ID: <443ba55d-aff1-1f36-e3e7-00df95f4abdc@FreeBSD.org> Date: Sun, 1 Aug 2021 23:47:35 -0400 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 4GdP8p3Fr2z4hXH X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Aug 2021 03:47:38 -0000 On 01.08.2021 23:43, Mateusz Guzik wrote: > Mostly related, I just had a look at the code and noticed: > > static uint32_t > sched_random(void) > { > uint32_t *rndptr; > > rndptr = DPCPU_PTR(randomval); > *rndptr = *rndptr * 69069 + 5; > > return (*rndptr >> 16); > } > > Except randomval starts at 0 for all CPUs. Should be easy to pre-init > with an actual random value. Is that something you played with? It is pretty old code, so no, at least not this time. But I doubt it would make a any difference, since different CPUs should have different number of calls to this, so they should naturally run away from each-other. -- Alexander Motin