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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 373B9C5DF60 for ; Fri, 8 Nov 2019 09:25:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B1F92178F for ; Fri, 8 Nov 2019 09:25:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qtpBO4Vl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730943AbfKHJZq (ORCPT ); Fri, 8 Nov 2019 04:25:46 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:59170 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730144AbfKHJZq (ORCPT ); Fri, 8 Nov 2019 04:25:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=iOfuQrgwDQHEEc9u8dvBDH4RtXgvlA6VBhp4ub5fX7E=; b=qtpBO4Vl5+z4b3XslqvkmHVCP 93vG3fG9QiTNctOzPlmdEhvbCGO54U5C6k+2DiOO6ByYnsFYRClscR2i/QV6XTzdWlGY7ROx2+l+1 xbZCvzAWPlZPkecRey8ZTHrlCMFPiF9dI4FsDGE0nVOT+zLr0KsPdCkxWIrib15ITCSPr3qofmMiW 19h3xkeHh2Kao+MjwEoPseuk3SNFShk1gGs0OTuYoAgXjeGlTpHVTD2BNw2fciehUQuhjcOZzWa15 mX8nZZ1tlY/RprWFB5Qy6e0Q0fsSfskSVlrwKLDYNkE7UaK/+n1xk/DEQuuxfcMR6loep2KZoikVc TOBJeyu5A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iT0WP-0007MK-N4; Fri, 08 Nov 2019 09:25:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 2502A301A79; Fri, 8 Nov 2019 10:24:29 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 058E12022B9E1; Fri, 8 Nov 2019 10:25:34 +0100 (CET) Date: Fri, 8 Nov 2019 10:25:33 +0100 From: Peter Zijlstra To: Shile Zhang Cc: Masahiro Yamada , Michal Marek , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Josh Poimboeuf , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org Subject: Re: [RFC PATCH 0/4] Speed booting by sorting ORC unwind tables at build time Message-ID: <20191108092533.GN5671@hirez.programming.kicks-ass.net> References: <20191107143205.206606-1-shile.zhang@linux.alibaba.com> <20191107152244.GD4114@hirez.programming.kicks-ass.net> <85abe498-f241-4752-81b5-6c0314f5a1e8@linux.alibaba.com> <20191108092136.GH4114@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191108092136.GH4114@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 08, 2019 at 10:21:36AM +0100, Peter Zijlstra wrote: > On Fri, Nov 08, 2019 at 09:42:55AM +0800, Shile Zhang wrote: > > > > Can sort{ex,orc}table() be ran concurrently? Do they want to be the same > > > (threaded) tool? > > > I think it is possible to do those sort work concurrently, likes deferred > > memory init which is big boot time speed up. > > But I don't know if the exception table and ORC unwind tables can be > > deferred, due to those tables might be used in early boot time, for early > > exception handling and early debugging. I'm not familiar with that. > > I meant at link time, run both sorts concurrently such that we only have > to wait for the longest, instead of the sum of them. > > They're not changing the same part of the ELF file, so it should be > possible to have one tool have multiple threads, each sorting a > different table. > > Aside from the .ex_table and ORC there's also .jump_table that wants > sorting (see jump_label_sort_entries()). Oh, and I'll be adding .static_call_sites soon, see: https://lkml.kernel.org/r/20191007082708.013939311@infradead.org (I should repost that) That gives us 4 tables to sort which we can do concurrently in 4 threads. > I agree that doing it at link time makes sense, I just hate to do all > this sorting in sequence and blowing up the link time. I don't build for > customers, I build for single use boot and linking _SUCKS_.