From mboxrd@z Thu Jan 1 00:00:00 1970 From: vilanova@ac.upc.edu (=?utf-8?Q?Llu=C3=ADs_Vilanova?=) Date: Thu, 18 Aug 2016 12:22:18 +0200 Subject: [lttng-dev] [Qemu-devel] [PATCH 0/6] hypertrace: Lightweight guest-to-QEMU trace channel In-Reply-To: <20160818094720.GA4850@stefanha-x1.localdomain> (Stefan Hajnoczi's message of "Thu, 18 Aug 2016 10:47:20 +0100") References: <147041636348.2523.2954972609232949598.stgit@fimbulvetr.bsc.es> <20160818094720.GA4850@stefanha-x1.localdomain> Message-ID: <87wpjeqsv9.fsf@fimbulvetr.bsc.es> Stefan Hajnoczi writes: > On Fri, Aug 05, 2016 at 06:59:23PM +0200, Lluís Vilanova wrote: >> The hypertrace channel allows guest code to emit events in QEMU (the host) using >> its tracing infrastructure (see "docs/trace.txt"). This works in both 'system' >> and 'user' modes. That is, hypertrace is to tracing, what hypercalls are to >> system calls. >> >> You can use this to emit an event on both guest and QEMU (host) traces to easily >> synchronize or correlate them. You could also modify you guest's tracing system >> to emit all events through the hypertrace channel, providing a unified and fully >> synchronized trace log. Another use case is timing the performance of guest code >> when optimizing TCG (QEMU traces have a timestamp). >> >> See first commit for a full description. >> >> Signed-off-by: Lluís Vilanova >> --- > CCing Steven Rostedt, Masami Hiramatsu, Luiz Capitulino, and LTTng folks > who have all looked into host/guest tracing solutions. [...] Oh, I wasn't aware of that. I'm certainly interested in collaborating. Cheers, Lluis