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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 CED46C43381 for ; Mon, 11 Mar 2019 13:59:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A970E2084F for ; Mon, 11 Mar 2019 13:59:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727637AbfCKN7i (ORCPT ); Mon, 11 Mar 2019 09:59:38 -0400 Received: from mail-qk1-f193.google.com ([209.85.222.193]:38769 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726592AbfCKN7d (ORCPT ); Mon, 11 Mar 2019 09:59:33 -0400 Received: by mail-qk1-f193.google.com with SMTP id z3so2721236qkf.5 for ; Mon, 11 Mar 2019 06:59:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=77FPPr8GBQjFVtWgXmaq2v1wGWOsJ9spQIX6jZegB34=; b=A5Ronxa5MZS7nfRlJnvW/TCIp8D+3gumXrOJZTMO+8de5s8FFRSm0rQEjaGxAUQ9j1 mG6xObsrEShrwROcN/WWqvHR3ao66Yfu+907p5Wc690M+csIaLJgYl2v7BkJ7b29Swrh HLl/VWAdcRIXarNXhwnYmxN2Dw6rmSNyNb+i91WrhQ35xix3xZLD+xfsbb54/6q2hOK0 rjhqjHLrgvPDXwtzMQTNuR6tpvLog3v4Lc2yB7wRTrzVTO9Wraykt9YDrLBKTaxiiKEn twVZrotic8o30PIwH8zH7COrDu8wLOJ1laa+880K6YRJyqepzz6cBDExcn5rvMR0Wox+ ZXNA== X-Gm-Message-State: APjAAAVOVNJWpfEjSXfgbo/JMPmEGp+LVsoYnOCYQ6KgIE5yP57/4qPu 5Ed5QoiTpq0asgqlDN2UoGO7xw== X-Google-Smtp-Source: APXvYqw9YjGDnhJ+1jlpw7LNXGz4dlHhYvGe+8BN/PnyfIJlcNuYvvhADur74p7uAUvRCtKs8Sg6Ow== X-Received: by 2002:a37:464f:: with SMTP id t76mr7443872qka.353.1552312772629; Mon, 11 Mar 2019 06:59:32 -0700 (PDT) Received: from redhat.com (pool-173-76-246-42.bstnma.fios.verizon.net. [173.76.246.42]) by smtp.gmail.com with ESMTPSA id r24sm3623959qte.60.2019.03.11.06.59.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Mar 2019 06:59:31 -0700 (PDT) Date: Mon, 11 Mar 2019 09:59:28 -0400 From: "Michael S. Tsirkin" To: Jason Wang Cc: Christoph Hellwig , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, peterx@redhat.com, linux-mm@kvack.org, aarcange@redhat.com, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org Subject: Re: [RFC PATCH V2 0/5] vhost: accelerate metadata access through vmap() Message-ID: <20190311095405-mutt-send-email-mst@kernel.org> References: <1551856692-3384-1-git-send-email-jasowang@redhat.com> <20190308141220.GA21082@infradead.org> <56374231-7ba7-0227-8d6d-4d968d71b4d6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <56374231-7ba7-0227-8d6d-4d968d71b4d6@redhat.com> Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: > > On 2019/3/8 下午10:12, Christoph Hellwig wrote: > > On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote: > > > This series tries to access virtqueue metadata through kernel virtual > > > address instead of copy_user() friends since they had too much > > > overheads like checks, spec barriers or even hardware feature > > > toggling. This is done through setup kernel address through vmap() and > > > resigter MMU notifier for invalidation. > > > > > > Test shows about 24% improvement on TX PPS. TCP_STREAM doesn't see > > > obvious improvement. > > How is this going to work for CPUs with virtually tagged caches? > > > Anything different that you worry? If caches have virtual tags then kernel and userspace view of memory might not be automatically in sync if they access memory through different virtual addresses. You need to do things like flush_cache_page, probably multiple times. > I can have a test but do you know any > archs that use virtual tag cache? sparc I believe. > Thanks 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,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 8BCAEC4360F for ; Mon, 11 Mar 2019 13:59:45 +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 5C3902084F for ; Mon, 11 Mar 2019 13:59:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="P8v19Q64" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C3902084F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=AtPq11RImlra6lc5jjKXdYVV2ZjTgYWYdtQLUOSn4UE=; b=P8v19Q64N4zV2H lFgowCpmcB+vbXdDH6ndi+mwHpb8kl5KNbU3dlUhZdEcxMOMtNS0iFLn2n/5rJo+S01WPN/Stke9z 0jo1g3rgNC+4BHUrRw1EXB7ovR2hQimLavnmvK7Y7ZnQUX9dUNtqC+x4UvvGUI63B3eDPAfrT1ogA 2GTyFq4MvWu6Hd5extg3VNQlSmIfv3Sqa/hjaaC+Ex+l3eEXBb+9UJg67+UV3b6wtpodPS0llkB6e KYE+fLJZNbnTSD66Y15y5FN+728pDFDKZayO00FWPj07YKBhLIBd4huQ2fxkzBx3W34fpvfse/mtq T1N4ksVefb2YmDdO1ilQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3LSs-0006hr-SZ; Mon, 11 Mar 2019 13:59:38 +0000 Received: from mail-qk1-f193.google.com ([209.85.222.193]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3LSp-0006gn-2Y for linux-arm-kernel@lists.infradead.org; Mon, 11 Mar 2019 13:59:37 +0000 Received: by mail-qk1-f193.google.com with SMTP id u22so2715533qkj.11 for ; Mon, 11 Mar 2019 06:59:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=77FPPr8GBQjFVtWgXmaq2v1wGWOsJ9spQIX6jZegB34=; b=qyI7iFvOqefh1bjTZKUc23VyvvitxNNIaXt5LK1iXqvwyaukboWNxxZpLkrTKWKggX Ndi2Zb1eQ0oPLxyN6pe+AMmxhTTKKWENQkqeWB7hpcRjFJqzi/oAJ7lETRcWlrmkaZe9 XIEmQjWgCGe3GF8S388km2c6yumsA7hbNSOC1ubxQbFXoDpcxpVdmNtmFgu3ERhA8Xsr cgoIWXWbCW2uf1FLM3hmoND2+L4YutB3c2OnsM0XqkSAn7kdNjounezDaPN6Fg2sw6aB 4/oS4XrnnZQyn2UdiXd7iJVchQHUIdC1yax+nOgoQFo+yIAy3SrP5odmUqpWRjAY1TUv IYHA== X-Gm-Message-State: APjAAAUwtMqo0EyhTFXBGF2LSLkou5ydfG4s1rCsiIYEw1/TJda3dvMR 0FPjPoRwvFwVQAgClTH2Pi5spA== X-Google-Smtp-Source: APXvYqw9YjGDnhJ+1jlpw7LNXGz4dlHhYvGe+8BN/PnyfIJlcNuYvvhADur74p7uAUvRCtKs8Sg6Ow== X-Received: by 2002:a37:464f:: with SMTP id t76mr7443872qka.353.1552312772629; Mon, 11 Mar 2019 06:59:32 -0700 (PDT) Received: from redhat.com (pool-173-76-246-42.bstnma.fios.verizon.net. [173.76.246.42]) by smtp.gmail.com with ESMTPSA id r24sm3623959qte.60.2019.03.11.06.59.30 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 11 Mar 2019 06:59:31 -0700 (PDT) Date: Mon, 11 Mar 2019 09:59:28 -0400 From: "Michael S. Tsirkin" To: Jason Wang Subject: Re: [RFC PATCH V2 0/5] vhost: accelerate metadata access through vmap() Message-ID: <20190311095405-mutt-send-email-mst@kernel.org> References: <1551856692-3384-1-git-send-email-jasowang@redhat.com> <20190308141220.GA21082@infradead.org> <56374231-7ba7-0227-8d6d-4d968d71b4d6@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <56374231-7ba7-0227-8d6d-4d968d71b4d6@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190311_065935_120007_6134DC11 X-CRM114-Status: GOOD ( 11.65 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aarcange@redhat.com, linux-parisc@vger.kernel.org, kvm@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, peterx@redhat.com, virtualization@lists.linux-foundation.org, Christoph Hellwig , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gTW9uLCBNYXIgMTEsIDIwMTkgYXQgMDM6MTM6MTdQTSArMDgwMCwgSmFzb24gV2FuZyB3cm90 ZToKPiAKPiBPbiAyMDE5LzMvOCDkuIvljYgxMDoxMiwgQ2hyaXN0b3BoIEhlbGx3aWcgd3JvdGU6 Cj4gPiBPbiBXZWQsIE1hciAwNiwgMjAxOSBhdCAwMjoxODowN0FNIC0wNTAwLCBKYXNvbiBXYW5n IHdyb3RlOgo+ID4gPiBUaGlzIHNlcmllcyB0cmllcyB0byBhY2Nlc3MgdmlydHF1ZXVlIG1ldGFk YXRhIHRocm91Z2gga2VybmVsIHZpcnR1YWwKPiA+ID4gYWRkcmVzcyBpbnN0ZWFkIG9mIGNvcHlf dXNlcigpIGZyaWVuZHMgc2luY2UgdGhleSBoYWQgdG9vIG11Y2gKPiA+ID4gb3ZlcmhlYWRzIGxp a2UgY2hlY2tzLCBzcGVjIGJhcnJpZXJzIG9yIGV2ZW4gaGFyZHdhcmUgZmVhdHVyZQo+ID4gPiB0 b2dnbGluZy4gVGhpcyBpcyBkb25lIHRocm91Z2ggc2V0dXAga2VybmVsIGFkZHJlc3MgdGhyb3Vn aCB2bWFwKCkgYW5kCj4gPiA+IHJlc2lndGVyIE1NVSBub3RpZmllciBmb3IgaW52YWxpZGF0aW9u Lgo+ID4gPiAKPiA+ID4gVGVzdCBzaG93cyBhYm91dCAyNCUgaW1wcm92ZW1lbnQgb24gVFggUFBT LiBUQ1BfU1RSRUFNIGRvZXNuJ3Qgc2VlCj4gPiA+IG9idmlvdXMgaW1wcm92ZW1lbnQuCj4gPiBI b3cgaXMgdGhpcyBnb2luZyB0byB3b3JrIGZvciBDUFVzIHdpdGggdmlydHVhbGx5IHRhZ2dlZCBj YWNoZXM/Cj4gCj4gCj4gQW55dGhpbmcgZGlmZmVyZW50IHRoYXQgeW91IHdvcnJ5PwoKSWYgY2Fj aGVzIGhhdmUgdmlydHVhbCB0YWdzIHRoZW4ga2VybmVsIGFuZCB1c2Vyc3BhY2UgdmlldyBvZiBt ZW1vcnkKbWlnaHQgbm90IGJlIGF1dG9tYXRpY2FsbHkgaW4gc3luYyBpZiB0aGV5IGFjY2VzcyBt ZW1vcnkKdGhyb3VnaCBkaWZmZXJlbnQgdmlydHVhbCBhZGRyZXNzZXMuIFlvdSBuZWVkIHRvIGRv IHRoaW5ncyBsaWtlCmZsdXNoX2NhY2hlX3BhZ2UsIHByb2JhYmx5IG11bHRpcGxlIHRpbWVzLgoK PiBJIGNhbiBoYXZlIGEgdGVzdCBidXQgZG8geW91IGtub3cgYW55Cj4gYXJjaHMgdGhhdCB1c2Ug dmlydHVhbCB0YWcgY2FjaGU/CgpzcGFyYyBJIGJlbGlldmUuCgo+IFRoYW5rcwoKCgoKX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbGludXgtYXJtLWtlcm5l bCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6 Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGluZm8vbGludXgtYXJtLWtlcm5lbAo=