From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10920 invoked by alias); 6 Oct 2018 01:24:57 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 412 invoked by uid 89); 6 Oct 2018 01:24:47 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=psymtab X-HELO: gateway30.websitewelcome.com Received: from gateway30.websitewelcome.com (HELO gateway30.websitewelcome.com) (192.185.179.30) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Sat, 06 Oct 2018 01:24:43 +0000 Received: from cm15.websitewelcome.com (cm15.websitewelcome.com [100.42.49.9]) by gateway30.websitewelcome.com (Postfix) with ESMTP id C4B111568C for ; Fri, 5 Oct 2018 20:24:41 -0500 (CDT) Received: from box5379.bluehost.com ([162.241.216.53]) by cmsmtp with SMTP id 8bKjgeSzw8YaU8bKjg6uEd; Fri, 05 Oct 2018 20:24:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=tromey.com; s=default; h=Content-Type:MIME-Version:Message-ID:In-Reply-To:Date: References:Subject:Cc:To:From: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=HarU53f/BVi62106V8/n7UBKRm3d3OUQXGOguphv+bg=; b=srvx0Ya7RKTkeJ2+oheeppVfML FltSv7FOdNqg94EwFXNwYuCFifs0o2TNITL9siMeDVP+u+bnCwxPQhRhYUOj03nlUWfryYnoHt7FM K/hCVL7v4mjzHOzOBSXfQeKpG; Received: from 97-122-190-66.hlrn.qwest.net ([97.122.190.66]:44262 helo=bapiya) by box5379.bluehost.com with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91) (envelope-from ) id 1g8bKj-003AsB-H4; Fri, 05 Oct 2018 20:24:41 -0500 From: Tom Tromey To: Tom Tromey Cc: Simon Marchi , gdb-patches@sourceware.org Subject: Re: [RFA 08/15] Remove readin and compunit_symtab fields from psymtab References: <20180510222357.27332-1-tom@tromey.com> <20180510222357.27332-9-tom@tromey.com> <5f8f38c4-8b4b-9fea-b9f2-7c69758a09c2@simark.ca> <87lg7mi5al.fsf@tromey.com> Date: Sat, 06 Oct 2018 01:24:00 -0000 In-Reply-To: <87lg7mi5al.fsf@tromey.com> (Tom Tromey's message of "Thu, 27 Sep 2018 23:01:38 -0600") Message-ID: <87zhvreujr.fsf@tromey.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-SW-Source: 2018-10/txt/msg00143.txt.bz2 >>>>> "Tom" == Tom Tromey writes: >>>>> "Simon" == Simon Marchi writes: Simon> As Pedro pointed out a few times, unordered_map is an hash map with open Simon> hashing. So we change what was previously a single pointer dereference Simon> to a lookup in a hash table, followed with a linear search in a linked Simon> list. If this map is looked up very frequently, maybe we should consider Simon> using an htab_t instead? Some profiling data would help, but it seems Simon> like psymtab_read_in_p is called quite a bit when looking up symbols... [...] Tom> I still haven't tried any performance measurements. Tom> I'm not quite sure what to try. I ran the gdb.perf tests and on some tests, it seems that the results are within the noise; but on backtrace (2048) and skip-function-3000 (4000) gdb is about 4% slower. I don't know if this is enough to worry about. Tom