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Wed, 09 Dec 2020 12:42:50 -0500 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-315-X0xuH_o0OL6hdCHuVG8nNw-1; Wed, 09 Dec 2020 12:42:46 -0500 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 D7896107ACE4; Wed, 9 Dec 2020 17:42:44 +0000 (UTC) Received: from localhost (ovpn-115-48.ams2.redhat.com [10.36.115.48]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3D9A96EF41; Wed, 9 Dec 2020 17:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607535767; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oSxOd1u8e3fJnH7nU1M1dxTh+HCkarFImSvjmmFt7EA=; b=fUmy23V/cYcYwm1HRNBTlNjtaVJhiEjZbHRlIRMBCyls4z9Vp4j6LaAgfrOGCH94dGWzMB G7+Rd3N+nC73GODWI18SqFho08Gi1+n8Jl654grLU06rHoYYSl2OvzSXT6zGkkeKGyt4oE P4Rqe50mUwPR1u8t2PrHpToVs/4Qacc= X-MC-Unique: X0xuH_o0OL6hdCHuVG8nNw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH 3/3] trace: recommend "log" backend for getting started with tracing Date: Wed, 9 Dec 2020 17:42:25 +0000 Message-Id: <20201209174225.401337-4-stefanha@redhat.com> In-Reply-To: <20201209174225.401337-1-stefanha@redhat.com> References: <20201209174225.401337-1-stefanha@redhat.com> MIME-Version: 1.0 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-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; 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: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_NONE=-0.0001, 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: Peter Maydell , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" The "simple" backend is actually more complicated to use than the "log" backend. Update the quickstart documentation to feature the "log" backend instead of the "simple" backend. Suggested-by: Peter Maydell Signed-off-by: Stefan Hajnoczi --- docs/devel/tracing.rst | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/docs/devel/tracing.rst b/docs/devel/tracing.rst index 76cc1b24fa..039a0bb267 100644 --- a/docs/devel/tracing.rst +++ b/docs/devel/tracing.rst @@ -11,9 +11,9 @@ for debugging, profiling, and observing execution. Quickstart =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 -1. Build with the 'simple' trace backend:: +1. Build with the 'log' trace backend:: =20 - ./configure --enable-trace-backends=3Dsimple + ./configure --enable-trace-backends=3Dlog make =20 2. Create a file with the events you want to trace:: @@ -24,10 +24,6 @@ Quickstart =20 qemu --trace events=3D/tmp/events ... # your normal QEMU invocation =20 -4. Pretty-print the binary trace file:: - - ./scripts/simpletrace.py trace-events-all trace-* # Override * with QE= MU - Trace events =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 @@ -195,7 +191,7 @@ script. =20 The trace backends are chosen at configure time:: =20 - ./configure --enable-trace-backends=3Dsimple + ./configure --enable-trace-backends=3Dlog =20 For a list of supported trace backends, try ./configure --help or see belo= w. If multiple backends are enabled, the trace is sent to them all. @@ -227,10 +223,11 @@ uses DPRINTF(). Simpletrace ----------- =20 -The "simple" backend supports common use cases and comes as part of the QE= MU -source tree. It may not be as powerful as platform-specific or third-party -trace backends but it is portable. This is the recommended trace backend -unless you have specific needs for more advanced backends. +The "simple" backend writes binary trace logs to a file from a thread, mak= ing +it lower overhead than the "log" backend. A Python API is available for wr= iting +offline trace file analysis scripts. It may not be as powerful as +platform-specific or third-party trace backends but it is portable and has= no +special library dependencies. =20 Monitor commands ~~~~~~~~~~~~~~~~ --=20 2.28.0