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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 43FC8C433DF for ; Wed, 3 Jun 2020 17:17:01 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 115BF20674 for ; Wed, 3 Jun 2020 17:17:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (4096-bit key) header.d=crudebyte.com header.i=@crudebyte.com header.b="CpydVC34" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 115BF20674 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:41774 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jgX0e-0006Cw-9f for qemu-devel@archiver.kernel.org; Wed, 03 Jun 2020 13:17:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52722) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgX04-0005jU-Lt for qemu-devel@nongnu.org; Wed, 03 Jun 2020 13:16:24 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:38209) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jgX03-0008Gl-4S for qemu-devel@nongnu.org; Wed, 03 Jun 2020 13:16:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=do8QewBWTwaUFMDOpMbrFcdPeqXI73yJMWSpFWFFSn0=; b=CpydVC34V8sciBnhYnwrlUFJJU I6h5+gR9Ay3Cv4ENVtBnWaKSRBL6LbOUKZZrix9wMtTy2pKr43ltdmmn1zI3ascimchdeUUweFNFo MI7P058XFK4l9ZhWVi1ln0jEpinU5OH+zirNTxLROrLJxSu9lyJWkvLmqL//reegrmLGS/3Yd3IsG p6oWO5fsQXwMaE6Yw0o0dNYPYwLAN828sHHimQYGGnzM8mfky8OxZDERQVO9HCJLQ2zzzWQQjkxDd STGYC3IkaQlv76wKlKWXUG4tyw2FlAAQv2MYFZASrkblouEcqckdu1MkrbisG7jVX4fI6nieXMn6N XkqWg1iwO37oeIJn69FHIwBVBt6AbTH3LqgxV45zpayi8/YJ24AWdQVQMxPhic1w9QRy0te7ntWZW sizGBcUT7mI5bfmgg/BfGz7QB6y8jAqL5TuT3KV0rwAPxwwgcpKNVX+j10so/U3hDE36+YFAAqOy3 trUmCur2xO2Rlmj8OLxOPNV1ElBg1gAAhHul0bLPw2X6Hlix1duR5JlxX25l8Zce6js/ZjCq0219e ByoPt84HicjGOfybIaxMsf/SezeUT8u8x5ocwhV54UMB+h9zyhtufhy0Z7H6d/s3aS1a588z2QRXY QT738+DdEQjh1j/GgrRohWiMYUm81L8Phn9m4U73M=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Greg Kurz Subject: Re: [PATCH v6 4/5] 9pfs: T_readdir latency optimization Date: Wed, 03 Jun 2020 19:16:08 +0200 Message-ID: <3959658.0YslYoXCm0@silver> In-Reply-To: <14ec5d880cfca878bf32e643243c7ab3f4a52440.1587309014.git.qemu_oss@crudebyte.com> References: <14ec5d880cfca878bf32e643243c7ab3f4a52440.1587309014.git.qemu_oss@crudebyte.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Received-SPF: pass client-ip=5.189.157.229; envelope-from=qemu_oss@crudebyte.com; helo=kylie.crudebyte.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/03 13:16:20 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sonntag, 19. April 2020 17:06:17 CEST Christian Schoenebeck wrote: > Make top half really top half and bottom half really bottom half: > > Each T_readdir request handling is hopping between threads (main > I/O thread and background I/O driver threads) several times for > every individual directory entry, which sums up to huge latencies > for handling just a single T_readdir request. > > Instead of doing that, collect now all required directory entries > (including all potentially required stat buffers for each entry) in > one rush on a background I/O thread from fs driver by calling the > previously added function v9fs_co_readdir_many() instead of > v9fs_co_readdir(), then assemble the entire resulting network > response message for the readdir request on main I/O thread. The > fs driver is still aborting the directory entry retrieval loop > (on the background I/O thread inside of v9fs_co_readdir_many()) > as soon as it would exceed the client's requested maximum R_readdir > response size. So this will not introduce a performance penalty on > another end. > > Signed-off-by: Christian Schoenebeck > --- > hw/9pfs/9p.c | 122 +++++++++++++++++++++++---------------------------- > 1 file changed, 55 insertions(+), 67 deletions(-) Ping. Anybody? I would like to roll out this patch set soon and this is the only patch in this series missing a review yet.