From patchwork Tue Mar 28 12:35:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 1762304 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=LRvl+oFz; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4Pm8Mw0PGPz1yXv for ; Tue, 28 Mar 2023 23:37:32 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ph8YR-0004EZ-KK; Tue, 28 Mar 2023 08:35:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ph8YO-0004BY-6l for qemu-devel@nongnu.org; Tue, 28 Mar 2023 08:35:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ph8YM-0006CV-QU for qemu-devel@nongnu.org; Tue, 28 Mar 2023 08:35:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680006954; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2rTzy4TesxCg60LU6meuGfbZE05Jvzsyuo/AaMdHhJ8=; b=LRvl+oFzBzUzft/Dm+Hdl1hyvNnG3/YJHLaII7TkQaGDu1D+SWRmBXkMed7bSCHEtU+5df pRJQbCxKIzyWVdbT5iqVulLQWTvLtsEFrSgsrWNw3lib2W6Sal23+/o9Ntb7Z7BudZHCay 0sYi3eUwm4ZJoBYa98t8QM5fKMFPdd8= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-27-R3vaBVX1NH6zthQCtUzxRQ-1; Tue, 28 Mar 2023 08:35:51 -0400 X-MC-Unique: R3vaBVX1NH6zthQCtUzxRQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A862E385556A; Tue, 28 Mar 2023 12:35:50 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.193.57]) by smtp.corp.redhat.com (Postfix) with ESMTP id EDA78C15BA0; Tue, 28 Mar 2023 12:35:49 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Subject: [PULL 1/4] nbd/server: push pending frames after sending reply Date: Tue, 28 Mar 2023 14:35:39 +0200 Message-Id: <20230328123542.222022-2-kwolf@redhat.com> In-Reply-To: <20230328123542.222022-1-kwolf@redhat.com> References: <20230328123542.222022-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Florian Westphal qemu-nbd doesn't set TCP_NODELAY on the tcp socket. Kernel waits for more data and avoids transmission of small packets. Without TLS this is barely noticeable, but with TLS this really shows. Booting a VM via qemu-nbd on localhost (with tls) takes more than 2 minutes on my system. tcpdump shows frequent wait periods, where no packets get sent for a 40ms period. Add explicit (un)corking when processing (and responding to) requests. "TCP_CORK, &zero" after earlier "CORK, &one" will flush pending data. VM Boot time: main: no tls: 23s, with tls: 2m45s patched: no tls: 14s, with tls: 15s VM Boot time, qemu-nbd via network (same lan): main: no tls: 18s, with tls: 1m50s patched: no tls: 17s, with tls: 18s Future optimization: if we could detect if there is another pending request we could defer the uncork operation because more data would be appended. Signed-off-by: Florian Westphal Message-Id: <20230324104720.2498-1-fw@strlen.de> Reviewed-by: Eric Blake Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- nbd/server.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/nbd/server.c b/nbd/server.c index a4750e4188..848836d414 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -2667,6 +2667,8 @@ static coroutine_fn void nbd_trip(void *opaque) goto disconnect; } + qio_channel_set_cork(client->ioc, true); + if (ret < 0) { /* It wasn't -EIO, so, according to nbd_co_receive_request() * semantics, we should return the error to the client. */ @@ -2692,6 +2694,7 @@ static coroutine_fn void nbd_trip(void *opaque) goto disconnect; } + qio_channel_set_cork(client->ioc, false); done: nbd_request_put(req); nbd_client_put(client);