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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4D7B8C38145 for ; Tue, 6 Sep 2022 08:23:15 +0000 (UTC) Received: from localhost ([::1]:40118 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oVTrW-0001Gt-7q for qemu-devel@archiver.kernel.org; Tue, 06 Sep 2022 04:23:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41630) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVTm7-0007Wz-Fo for qemu-devel@nongnu.org; Tue, 06 Sep 2022 04:17:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:60487) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oVTm0-0002AG-IY for qemu-devel@nongnu.org; Tue, 06 Sep 2022 04:17:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662452252; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=oqLHtBKy/V3giRuWxnYHs821O4uHxlNtGLZqUN1lQhg=; b=b6yFSeV0s/y90Ofc01yqJHQ/bIrHbutFuYBNHz6vAwSO/Dy8JO2UBWR57l1rsL6M6iANks PSu8Kjy2WeuugxyGz1XR5VV71B8w9trFs42J7ZMCXDeQ3rC5gJ3PtOC7HMEwSnr0pX8Fwn TO9nGmkvJjsgqcVJo0qBQWLSkJGj2tg= 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-515-esxTGp38M-qu7YO8PM0Ujw-1; Tue, 06 Sep 2022 04:17:28 -0400 X-MC-Unique: esxTGp38M-qu7YO8PM0Ujw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7B9FA299E745; Tue, 6 Sep 2022 08:17:28 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.166]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5632C1121314; Tue, 6 Sep 2022 08:17:28 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 1C54D21E6900; Tue, 6 Sep 2022 10:17:27 +0200 (CEST) From: Markus Armbruster To: Peter Maydell Cc: Claudio Fontana , qemu-devel Subject: Re: sphinx-build is really slow, any way to improve that? References: <53b94520-f02b-aef5-b372-0460531b566f@suse.de> Date: Tue, 06 Sep 2022 10:17:27 +0200 In-Reply-To: (Peter Maydell's message of "Mon, 5 Sep 2022 22:21:55 +0100") Message-ID: <87h71k533c.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Peter Maydell writes: > On Mon, 5 Sept 2022 at 20:51, Claudio Fontana wrote: >> when I build qemu, there is a lot of time spent at the end of the build where one cpu goes 100% on sphinx-build. >> >> Is there some way to parallelize that? It seems it is the current bottleneck for rebuilds for me.. > > It's a big fat python program, so I suspect not, but > maybe I'm wrong. > > You can always configure --disable-docs if you don't care > about the docs and want to make builds faster. I care about the docs, but the impact on turnaround time is so bad I stopped building the docs in the build trees I use for development, and instead keep a separate tree that has docs enabled. Tends to delay diagnosis of doc markup errors, but that's the lesser evil for me. We used to have a similar problem with generated C: touch the QAPI schema, rebuild everything and its dog. That was because everything and its dog depended on the generated QAPI header. C projects 101: putting everything in a single header slows down rebuilds. We solved this by splitting up the generated header, and updating generated headers only when they actually change. I have no idea whether Sphinx could do a similarly incremental rebuild.