On Mon, Aug 14, 2017 at 05:39:08PM +0100, Daniel P. Berrange wrote: > 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 <berra...@redhat.com> > Date: Tue Oct 4 14:35:50 2016 +0100 > > trace: emit name <-> ID mapping in simpletrace header > > entirely ?
Follow-up to my reply: We can revert just the changes to simpletrace_stap.py. This means: 1. Event ID mapping records are no longer emitted. 2. No simpletrace file header is emitted. I like this idea because it's simpler than my current patch. Users will have to use the ./simpletrace.py --no-header option again when printing simpletrace.stp traces, but that isn't a problem. Stefan
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