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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C61E2C606CF for ; Tue, 9 Jul 2019 00:29:35 +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 9216F20693 for ; Tue, 9 Jul 2019 00:29:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Hh4VMFlB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9216F20693 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jonmasters.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Subject:In-Reply-To:MIME-Version:Date: Message-ID:References:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Uuwb0SVkDv9bil79UvNU+LEeyYu1O6SUkWck7LgAwVQ=; b=Hh4VMFlBOT8Ot/ zeeRNHSBdm6HI+ZIl8eiC9SAVVp/1lxkfmGyRv3vNFC/8TSLSfBJWaUW4YZE3jUE58WrRobCW6gV7 jA7p82b4b10oyE5OPRGTW96P0/u7Ev8EUoI+aDd7M6gyxUEGFSzoZVSS5zZ+EvKnjF1yzflmIm/JX HHULn/6bPPQqY0gincBCzpifZdCMtRXTGStvo+gIc6/SQOx+fLn4SaDAviFTxd99WUmiN4l/0K+Fo f1wgEXjREk+TntoH6MKQw1ift0vmOM+AeZfeSnM3UstPXhUMRlRXdaLcMmw+T0YMxmUcSJiGZmaIw 08+P/hNVV79yjE2ieirA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hke0i-0007xZ-5r; Tue, 09 Jul 2019 00:29:32 +0000 Received: from edison.jonmasters.org ([173.255.233.168]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hke0e-0007x7-Tp for linux-arm-kernel@lists.infradead.org; Tue, 09 Jul 2019 00:29:30 +0000 Received: from boston.jonmasters.org ([50.195.43.97] helo=tonnant.bos.jonmasters.org) by edison.jonmasters.org with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hke0d-0003pR-Ii; Tue, 09 Jul 2019 00:29:27 +0000 From: Jon Masters To: "qi.fuli@fujitsu.com" , Will Deacon References: <20190617143255.10462-1-indou.takao@jp.fujitsu.com> <20190617170328.GJ30800@fuggles.cambridge.arm.com> <20190627102724.vif6zh6zfqktpmjx@willie-the-truck> <5999ed84-72d0-9d42-bf7d-b8d56eaa4d4a@jp.fujitsu.com> <675313fe-007b-c850-d730-a629b82ccfc8@jonmasters.org> Message-ID: Date: Mon, 8 Jul 2019 20:29:26 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <675313fe-007b-c850-d730-a629b82ccfc8@jonmasters.org> Content-Language: en-US X-SA-Exim-Connect-IP: 50.195.43.97 X-SA-Exim-Mail-From: jcm@jonmasters.org Subject: Re: [PATCH 0/2] arm64: Introduce boot parameter to disable TLB flush instruction within the same inner shareable domain X-SA-Exim-Version: 4.2.1 (built Sun, 08 Nov 2009 07:31:22 +0000) X-SA-Exim-Scanned: Yes (on edison.jonmasters.org) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190708_172929_031059_6DA1F1FE X-CRM114-Status: GOOD ( 13.35 ) 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: Jonathan Corbet , "peterz@infradead.org" , Catalin Marinas , "linux-doc@vger.kernel.org" , Will Deacon , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "indou.takao@fujitsu.com" 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 7/8/19 8:25 PM, Jon Masters wrote: > On 7/2/19 10:45 PM, qi.fuli@fujitsu.com wrote: > >> However, we found that with the increase of that the TLB flash was called, >> the noise was also increasing. Here we understood that the cause of this >> issue is the implementation of Linux's TLB flush for arm64, especially use of >> TLBI-is instruction which is a broadcast to all processor core on the system. > > Are you saying that for a microbenchmark in which very large numbers of > threads are created and destroyed rapidly there are a large number of > associated tlb range flushes which always use broadcast TLBIs? > > If that's the case, and the hardware doesn't do any ASID filtering and > each TLBI results in a DVM to every PE, would it make sense to look at > whether there are ways to improve batching/switch to an IPI approach > rather than relying on broadcasts, as a more generic solution? What I meant was a heuristic to do this automatically, rather than via a command line. Jon. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel