From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=gnu.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=gnu.org 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 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=i+bIzdtJuMWtlE2i4uYGde9lodieU9QoUaTCuyBxfaw=; b=jc4191P7E56r A3OSXb6e4tlxJ9VLhY9lCn1digYen5Xw+FtduLyynxGPbUOzIEpaDVtwOHBynf3VvwKsJcwD7q41+ P6dkuMF4gX/tXe/f6qsf/W6XMpoSbrGacSu/bH5aaRKzul/Ygfj0L5bjrqbUnN/TrNN2O0pwY/K3s 4qvxCRsYUVFGD+CkWhGBFP68QluHp+uE/RnebThHiZr/8KPwpqXlfKUe5De/pewgmIHSmso8qlTLk ORFV3K6iOXIQc3M7Bmlmm2ecCMQFYblLMGivEco5f8uzmSDAdscsPf2cIdnQfFdiDmQlMzTcA2XBr A2eFGOnTRhleu/HIJi90zQ==; 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> From: Eli Zaretskii 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-Spam-Status: No, score=1.9 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_BARRACUDACENTRAL,SPF_HELO_PASS,SPF_PASS,TXREP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Level: * X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: > 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?