From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id +GKcHDF5oGNkZAUAWB0awg (envelope-from ) for ; Mon, 19 Dec 2022 09:46:09 -0500 Received: by simark.ca (Postfix, from userid 112) id 7319D1E222; Mon, 19 Dec 2022 09:46:09 -0500 (EST) Authentication-Results: simark.ca; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.a=rsa-sha256 header.s=default header.b=FXazWflG; dkim-atps=neutral X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-5.3 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Received: from sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 29CDC1E0D3 for ; Mon, 19 Dec 2022 09:46:09 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id F3DC93858C50 for ; Mon, 19 Dec 2022 14:46:07 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F3DC93858C50 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1671461168; bh=krE+hTvXqtEzfNZAnn/rscWRDXbSgtFE2POAnjJHGxU=; h=Date:To:Cc:In-Reply-To:Subject:References:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=FXazWflGH009CyxOzZjrSRgNihW4KVHlTncGCPSON6mVKTjv3eDN7U7YBzMeS3ad3 Od5Pg1vBH5XL/W0SwH9Hl0+jmDOCLU/ow+EKCQDQir7Izad7ckr4bksKPV6RcKzkcT kO9HUY6WIwi0qHqXXaHLbDYaHxLjTusxpjHvaGk0= Received: from eggs.gnu.org (eggs.gnu.org [IPv6:2001:470:142:3::10]) by sourceware.org (Postfix) with ESMTPS id B56223858C2F for ; Mon, 19 Dec 2022 14:45:46 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B56223858C2F Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p7HOj-0003qF-VZ; Mon, 19 Dec 2022 09:45:45 -0500 Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p7HOj-0007bX-9D; Mon, 19 Dec 2022 09:45:45 -0500 Date: Mon, 19 Dec 2022 16:45:55 +0200 Message-Id: <835ye7e9jw.fsf@gnu.org> To: Luis Machado , Tom Tromey Cc: gdb-patches@sourceware.org In-Reply-To: (message from Luis Machado on Mon, 19 Dec 2022 14:08:27 +0000) Subject: Re: Two observations using GDB 13 snapshot References: <83h6xugc5v.fsf@gnu.org> <58b64bf8-90b6-d080-c060-d03761501199@arm.com> <83k02neezy.fsf@gnu.org> X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Eli Zaretskii via Gdb-patches Reply-To: Eli Zaretskii Errors-To: gdb-patches-bounces+public-inbox=simark.ca@sourceware.org Sender: "Gdb-patches" > Date: Mon, 19 Dec 2022 14:08:27 +0000 > Cc: gdb-patches@sourceware.org > From: Luis Machado > > On 12/19/22 12:48, Eli Zaretskii wrote: > > This build is without std::thread. Maybe it's related? > > Well, if the worker threads are disabled and things are read by a single thread, that may explain some slowness. But I don't think it would be as slow as you describe. > > > > > Does GDB 13 read DWARF debug info significantly differently than > > previous versions? > > > > Do you see this on GNU/Linux, when debugging GDB with itself, if you > > disable multithreaded DWARF reading? > > For a regular build of GDB 13 (threaded), I see a pretty quick startup (about 3.5 seconds) to start gdb within gdb. > > With a GDB 13 built with threading disabled, I see about 15 seconds to do the same. > > Now, I noticed -readnow doesn't seem to use the worker threads for reading symbols, so passing that option slow things down significantly, to the point it takes 2 minutes to read the symbols. > > I don't know if that's on purpose. Thanks. Tom, could you please chime in? What could explain such a slowdown using -readnow and in the MinGW build without worker threads (since GDB 12 didn't use threads, either)? And why -readnow is so different from a GDB built without threading?