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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 AA843C433DB for ; Wed, 3 Feb 2021 16:42:26 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E03A864F7C for ; Wed, 3 Feb 2021 16:42:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E03A864F7C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40586 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l7LEW-0000vO-Qj for qemu-devel@archiver.kernel.org; Wed, 03 Feb 2021 11:42:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54788) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l7L4k-0007kg-Oe for qemu-devel@nongnu.org; Wed, 03 Feb 2021 11:32:18 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:44506) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l7L4h-0003xN-Nd for qemu-devel@nongnu.org; Wed, 03 Feb 2021 11:32:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612369935; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=1HxJrfCGp0uazMXjy4IL7yhg7W9zzN/PPCbuvWCVMLc=; b=dDiLQPrUCJv4Q2W/L3dhCDZ2SgvQVP15SDDTaJys1JVTNuCOS37QrDKqgk25lOavP/k/q4 CvYYYCa3D+UO2TieUv25BaTwIfA8U/GTlI1PVEjCPfkdiWJqJ1zQRAglZWFKGljsLKvtsD kV4I7zrbtlXwTspR/qEiwKliKJu7nvU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-275-vr3iQduYNEycvaRLLssIaQ-1; Wed, 03 Feb 2021 11:32:12 -0500 X-MC-Unique: vr3iQduYNEycvaRLLssIaQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E8AF385B6C0 for ; Wed, 3 Feb 2021 16:32:11 +0000 (UTC) Received: from localhost (ovpn-115-141.ams2.redhat.com [10.36.115.141]) by smtp.corp.redhat.com (Postfix) with ESMTP id 903EE60D07; Wed, 3 Feb 2021 16:32:08 +0000 (UTC) Date: Wed, 3 Feb 2021 16:32:02 +0000 From: Stefan Hajnoczi To: Gerd Hoffmann Subject: Re: [PATCH v3 0/8] [RfC] fix tracing for modules Message-ID: <20210203163202.GF241524@stefanha-x1.localdomain> References: <20210121125028.3247190-1-kraxel@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210121125028.3247190-1-kraxel@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="cz6wLo+OExbGG7q/" Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -32 X-Spam_score: -3.3 X-Spam_bar: --- X-Spam_report: (-3.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.539, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Markus Armbruster , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --cz6wLo+OExbGG7q/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 21, 2021 at 01:50:20PM +0100, Gerd Hoffmann wrote: > First version that actually works. Only qxl covered for this RfC, > other modules will follow once the basics are hashed out. >=20 > v3: > - handle initialization of modular tracepoints. Cool, this looks promising! > TODO: > Enabling modular tracepoints via -trace cmd line doesn't work yet. > Guess we need to store the list somewhere for later re-processing. > Error handling is tricky, specifically the "tracepoint doesn't exist" > error. Suggestions / ideas are welcome. Two ideas: Global trace event name list ---------------------------- Build *some* global information about all trace events, including modules, into the main QEMU binary. For example, generate an array of all trace event names so QEMU can always print an error if a non-existent trace event name is used. (This is similar to the trace-events-all file, which is a global list of all trace events.) Module name prefixes -------------------- Allow an optional module/group prefix like qxl:my_trace_event. When the user says: --trace qxl:my_trace_event QEMU knows that this trace event belongs to the "qxl" module/group. It will not attempt to load it until the qxl module registers itself. If "my_trace_event" doesn't exist in the qxl module: 1. If the qxl module is not loaded we don't hit an error. Nevermind. 2. When the qxl module is loaded pending events are resolved and an error is printed. --cz6wLo+OExbGG7q/ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmAa0AIACgkQnKSrs4Gr c8iokQgAmWg1eRLe6SyDD8mbj4+6x6Z4m7bxQFgJXxcg+Amk/ToetwzIj60LduGL dyWD70x8DByOotfDdgzbRj4o0eUTHPU0F+fwhsrjai8ZhcHmG/51S+OmSd+UofP0 /fmsUL/PGtyGpQ4EeCJunSfv2ao8mqGxJ+WnwCDIg4tBxYC3QAvH3MBHRyY+gpNa oojhT/m5wV7VPc4Xw91iejNWX2mOGxhxo10vEcKY0w4SQkpQqe4mfWq/MxREkyiz 9mk7RvncZmTcknfy4oJX3Y2+3b3iLBE6fx2/Az5EX4g3eiAHDVN/VUBq5d0pYSj3 GIqdDU2EcVLu9JQfSvfQpZb9Ny0yHA== =7wUN -----END PGP SIGNATURE----- --cz6wLo+OExbGG7q/--