From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35889) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dhIOe-0001sb-MC for qemu-devel@nongnu.org; Mon, 14 Aug 2017 12:39:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dhIOa-0000m4-NW for qemu-devel@nongnu.org; Mon, 14 Aug 2017 12:39:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55458) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dhIOa-0000ll-H4 for qemu-devel@nongnu.org; Mon, 14 Aug 2017 12:39:16 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 64A0BC000724 for ; Mon, 14 Aug 2017 16:39:15 +0000 (UTC) Date: Mon, 14 Aug 2017 17:39:08 +0100 From: "Daniel P. Berrange" Message-ID: <20170814163908.GG8506@redhat.com> Reply-To: "Daniel P. Berrange" References: <20170814162142.29666-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170814162142.29666-1-stefanha@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-2.10 0/2] trace: fix simpletrace.stp flight recorder mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org On Mon, Aug 14, 2017 at 05:21:40PM +0100, Stefan Hajnoczi wrote: > The SystemTap flight recorder mode no longer works with simpletrace.stp because > the event ID mapping records are emitted the first time an event fires. > Chances are, the event ID mapping record will not be in ring buffer when the > users wants to print the trace. > > This series solves the issue by using the trace-events-all global event > ordering for event IDs for simpletrace.stp. I see the way you've written it means it'll still honour the event id mappings in the header, if present, but I wonder what's the point of keeping that anymore ? If we need to support this ring-buffer mode, there's no way we can take advantage of having the ID mappings dynamically defined - we must always guarantee a stable mapping. IOW, should we just revert commit 7f1b588f20d027730676e627713ae3bbf6baab04 Author: Daniel P. Berrange Date: Tue Oct 4 14:35:50 2016 +0100 trace: emit name <-> ID mapping in simpletrace header entirely ? Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|