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=-20.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_NONE 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 6774EC2B9F4 for ; Mon, 28 Jun 2021 10:22:00 +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 1B08361C6B for ; Mon, 28 Jun 2021 10:22:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B08361C6B 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]:32846 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lxoOt-0000nd-6d for qemu-devel@archiver.kernel.org; Mon, 28 Jun 2021 06:21:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57918) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxoNM-0007tv-30 for qemu-devel@nongnu.org; Mon, 28 Jun 2021 06:20:24 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:56197) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lxoNI-0000z6-6Z for qemu-devel@nongnu.org; Mon, 28 Jun 2021 06:20:23 -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=8037QNi9hBcNOkxITZZnOyVJdujnu9Cv6zaOsSawrKE=; b=AXE8PwJ/JBOzkD3dgbc9/Mi4Ws P0TKodE2XFnyvPvxaRSecRxr4V7RzK2I8Nd7+gIS6VRlRfXlRAoRUBYkiETK8a/+RXJI706zwjLI4 x0JtV1V8eedNzvPCzR2j8+bkt4g7Xsahn8jIp8noDQGxt9H2K+4hY6uL9Lu37v8yE1f3d+iBeeRW/ 6rz5HJgAZ1gi4xECnX6p7i+uMAGeg2QBaS3ktpnRAXbdTs6eJpl/m0TUgX/Dx7wSdY/H7sKEjtZXm oAL/kSLPNJX2Dq6PdQ0s6TDfB0MKjlc/flZ2c1a9iXPCCJivxI0RSqst9w1h0z9I6N5tFKYe1kwCE C4d0VtW7u0y/WxuXAp2R96KYldWBbE+ROUp4FLzBUF1wKEJlDJ+M+xDiCGN0r4CmGuGtRs/Ia8oMS MJ96xU7VFUW7q2TuGjqx0syuxbmL9eJr8ObOWiue0Yaw3hk6vXjjRAM9QeamJmmE2uFsKmKrEBt33 tzC1zuq88QmYJFIOPadcLatUKTL1O29Idu6zaGHxfOZ81E5+uBHuX28dEAB9Y2TKRDYvO2WC0Q4Ev Rl23mSvuo6sYpsbFNRw7SZQWyim1ZGxmj3eizKpxo7yqcS4DbNgSxXHYNF3a/XvaU5A+FenZwuNcG xZXtyXbRrdz8oRvFN0fIvsxKb2k7n1qMpZJoXFKN8=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Greg Kurz Subject: Re: [PATCH v2 0/7] 9pfs: Twalk optimization Date: Mon, 28 Jun 2021 12:20:13 +0200 Message-ID: <1825400.NJsdj0r9HH@silver> In-Reply-To: <2022289.dxTFu3Ykd5@silver> References: <20210604183128.23142868@bahia.lan> <2022289.dxTFu3Ykd5@silver> 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-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_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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 Freitag, 4. Juni 2021 20:23:21 CEST Christian Schoenebeck wrote: > On Freitag, 4. Juni 2021 18:31:28 CEST Greg Kurz wrote: > > On Fri, 4 Jun 2021 17:48:49 +0200 > > > > Christian Schoenebeck wrote: > > > This patch set reduces latency of Twalk handling by reducing the amount > > > of > > > thread hops, similar to previous Treaddir optimization. > > > > > > The performance gain of this patch set is not as spectacular as > > > previously > > > with Treaddir, but there is definitely a measurable difference. > > > > > > The actualy performance optimization is patch 7. With the benchmark of > > > patch 2, the runtime of the Twalk test was cut in half. In real world > > > tests > > > I measured a performance gain (i.e. running an entire guest OS, and > > > hence > > > mixed with all other kinds of 9p requests) of about 2%, again measured > > > in > > > a > > > mix, not concentrated on Twalk alone. > > > > > > v1 -> v2: > > > * Added a separate [NEW PATCH 1] for fixing not_same_qid() semantic. > > > > Strangely, patch 1 appears between patch 3 and 4 in my email client. > > My bad, I forgot to take care about the time stamps of the individual > patches this time. > > > > * Code style: use sizeof(var-name) instead of sizeof(type-name) > > > > > > [PATCH 3]. > > > > > > * Split out dropping fid_to_qid() into separate [PATCH 4]. > > > > > > * Split out replacing not_same_qid() by same_stat_id() into separate > > > > > > [PATCH 5]. > > > > > > * Split out dropping root_qid into separate [PATCH 6]. > > > > I could have a look at all the patches except the last one. LGTM. > > You can add my R-b for patches 1 and 3 to 6. > > > > Reviewed-by: Greg Kurz > > Queued patches 1, 3..6 on 9p.next: > > https://github.com/cschoenebeck/qemu/commits/9p.next > > Thanks! > > > I'll try to find some time for patch 7 next week. > > Twalk can be tricky, so no hurry! It takes what it takes. > > > > Christian Schoenebeck (7): > > > 9pfs: fix not_same_qid() > > > 9pfs: Twalk benchmark > > > 9pfs: capture root stat > > > 9pfs: drop fid_to_qid() > > > 9pfs: replace not_same_qid() by same_stat_id() > > > 9pfs: drop root_qid > > > 9pfs: reduce latency of Twalk > > > > > > hw/9pfs/9p.c | 128 +++++++++++++++++++++++------------ > > > hw/9pfs/9p.h | 2 +- > > > tests/qtest/virtio-9p-test.c | 30 ++++++++ > > > 3 files changed, 116 insertions(+), 44 deletions(-) Ping How is your schedule Greg? Any chance for a time slice on this one? Best regards, Christian Schoenebeck