From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id ixkMAGcroWO51AUAWB0awg (envelope-from ) for ; Mon, 19 Dec 2022 22:26:31 -0500 Received: by simark.ca (Postfix, from userid 112) id E52B21E222; Mon, 19 Dec 2022 22:26:30 -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=OPeJIVxP; 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=-8.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, 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 E1E381E0D3 for ; Mon, 19 Dec 2022 22:26:29 -0500 (EST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 6359A3858D1E for ; Tue, 20 Dec 2022 03:26:29 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6359A3858D1E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1671506789; bh=i+bIzdtJuMWtlE2i4uYGde9lodieU9QoUaTCuyBxfaw=; 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=OPeJIVxPum1sbD4wPkmKXvR8kF7ua/niJncOFEEuC/qXnI0TfIlBDILcF/aw2jedj Kziyzo2JEinK+g0qHn1oaWIv9T8lLEEwYIDXtj3XQ5m59JWAKBKo1pOiMVMr0lCnqV syHYmjjNI6eaUImQ64lHuicbJQGEccDM+2J419EM= Received: from eggs.gnu.org (eggs.gnu.org [IPv6:2001:470:142:3::10]) by sourceware.org (Postfix) with ESMTPS id 209D13858D1E for ; Tue, 20 Dec 2022 03:26:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 209D13858D1E 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 1p7TGa-0002SS-Qa; Mon, 19 Dec 2022 22:26:08 -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 1p7TGa-0003y1-4T; Mon, 19 Dec 2022 22:26:08 -0500 Date: Tue, 20 Dec 2022 05:26:20 +0200 Message-Id: <83mt7idacj.fsf@gnu.org> To: Tom Tromey Cc: gdb-patches@sourceware.org, luis.machado@arm.com In-Reply-To: <87h6xrks77.fsf@tromey.com> (message from Tom Tromey on Mon, 19 Dec 2022 14:18:52 -0700) Subject: Re: Two observations using GDB 13 snapshot References: <83h6xugc5v.fsf@gnu.org> <58b64bf8-90b6-d080-c060-d03761501199@arm.com> <83k02neezy.fsf@gnu.org> <835ye7e9jw.fsf@gnu.org> <87h6xrks77.fsf@tromey.com> 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" > From: Tom Tromey > Cc: Luis Machado , Tom Tromey , Eli > Zaretskii > Date: Mon, 19 Dec 2022 14:18:52 -0700 > > >>>>> "Eli" == Eli Zaretskii via Gdb-patches writes: > > Eli> Tom, could you please chime in? What could explain such a slowdown > Eli> using -readnow and in the MinGW build without worker threads (since > Eli> GDB 12 didn't use threads, either)? And why -readnow is so different > Eli> from a GDB built without threading? > > Just a quick answer for now, I haven't tried to reproduce or > investigate... > > -readnow should not really be affected by the DWARF scanner rewrite. > With -readnow, all the new code is bypassed anyway. For quite a while > now, -readnow (when using DWARF anyway) has operated on the principle > that since gdb is reading full symbols, it might as well not bother with > partial symbols (or now, the index). > > Threads also should not matter here, because only the initial scan can > use multiple threads. The full symbol reader is single-threaded and > hasn't changed in any deep way since GDB 12. > > It's possible that some other change affected this -- the DWARF reader > in general sees a lot of patches. I don't know which one it might be > offhand, though. So you are saying that the rewrite of the DWARF scanner could be the reason for the slowness? Let me know if I can provide any additional information that could be useful in investigating this. Would it be useful to open a bugzilla issue?