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=-20.8 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_PASS, URIBL_BLOCKED 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 C0B03C4743D for ; Fri, 4 Jun 2021 18:27:09 +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 4095B613F1 for ; Fri, 4 Jun 2021 18:27:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4095B613F1 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]:52206 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lpEXE-0005Mj-F3 for qemu-devel@archiver.kernel.org; Fri, 04 Jun 2021 14:27:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42804) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lpETi-0003Pw-3S for qemu-devel@nongnu.org; Fri, 04 Jun 2021 14:23:30 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:59153) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lpETd-0000nu-AN for qemu-devel@nongnu.org; Fri, 04 Jun 2021 14:23:29 -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=8sgYhNfYdBTjy8pUefMu9BJT6+D0M10LX8FPgMGYjOw=; b=C42Et3ekUHVS1Li0xkNs5eHEmQ IDWKmVjAmPmlXmNcYqzakbPRN+8z6ayFGEM07Q05PD/dqGouOmx6AUxfm/W1ayovFhCoy90wVaLG2 y7R/eXlZGbgF44nmxF3O6eOzOGq2AYguYIUiVFVCWedu2X+RaU4pR3+EIz9zBeYqO2L0ffkKpwAGU 8/1tzRCyyg9UJHzRSy604h7Ez7eNMRGjyeCN3bfwlVdmikF3hNcmQd98wDNlzkMimE6J+WfTAIAy+ R0qALuZvztqLYy8YJobf6YhY8QrExKP6FWtQcHT1okXPykvbVh5SU4gZTairqPY6tEBVq9nYktsaL doR4xLyCYlDDExvh8qEjToHRPLmTUWKi+ERd0KeJ6A9jRqSK+FXK25G+p7VJKvGeeIgaRksqBvae/ 91KuWu9JqtM0zVXybxkaqnZxwg2+E5VJaBBad9a/F9RUF9oIazYHgq4bzVKfEztINpAkUPAbf7ry6 rrCTWwvBFcmA5yq5Vab6JnqkHbo1UNJ9FD+Y1RfyIhfUV4NNABBihUsitDOfehPSykvxBYRhZPyBs I/Z+GZjL+CfwGlkVHp1hNwpqXatVZkdZ9lacGKna8AOSm8PqNUaGY67HMvZyXRWMncIgLSzghgM5n k+ExscsO+vK1WndjDqGoTeAPin9ClscauwSk8TCds=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Greg Kurz Subject: Re: [PATCH v2 0/7] 9pfs: Twalk optimization Date: Fri, 04 Jun 2021 20:23:21 +0200 Message-ID: <2022289.dxTFu3Ykd5@silver> In-Reply-To: <20210604183128.23142868@bahia.lan> References: <20210604183128.23142868@bahia.lan> 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 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(-) Best regards, Christian Schoenebeck