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Re: [Qemu-devel] [PATCH v11 0/7] trace: Generic event state description
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH v11 0/7] trace: Generic event state description |
Date: |
Tue, 5 Mar 2013 10:34:30 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Mar 04, 2013 at 10:01:43PM +0100, Lluís Vilanova wrote:
> Stefan Hajnoczi writes:
>
> > On Fri, Mar 01, 2013 at 04:29:35PM +0100, Lluís Vilanova wrote:
> >> Provides a generic event state description structure (TraceEvent) and a
> >> more
> >> detailed event control and query interface.
> >>
> >> This is achieved by creating a new "non-public" tracing backend (i.e., not
> >> selectable by the user at configure time) that will generate the
> >> appropriate
> >> event description information.
> >>
> >> Signed-off-by: Lluís Vilanova <address@hidden>
> >> ---
> >>
> >> Changes in v11:
> >>
> >> * Rebase on a4bcea3 from master.
>
> > Hi Lluís,
> > Thanks for rebasing. Unfortunately I still hit the hang on shutdown
> > with the simple trace backend.
>
> > Steps to reproduce:
> > $ ./configure --target-list=x86_64-softmmu --enable-trace-backend=simple
> > $ make
> > $ cat my-events
> > bdrv_open_common
> > $ x86_64-softmmu/qemu-system-x86_64 \
> > -enable-kvm -m 1024 \
> > -trace events=my-events \
> > -drive if=virtio,cache=none,file=test.img
> > Ctrl-Alt-2
> > (qemu) quit
> > ...hang...
>
> > Please let me know if you are able to reproduce it. qemu.git/master
> > does not behave this way.
>
> I've been unable to reproduce it with v11, but was able to using v10 (although
> only a couple of times).
>
> What I saw in v10 looked like a deadlock between 'flush_trace_file' and
> 'wait_for_trace_records_available' (both use 'trace_lock'), but I only was
> able
> to reproduce it a couple of times, so I couldn't haunt the problem down.
>
> After a quick re-read of the patches, the changes should have no effect on how
> the mutexes in the "simple" backend are handled, so maybe the problem is not
> related to this change (it just makes it more frequent in your build).
I'll take a look here since it reproduces every time on this host.
> Could it be possible that you exit QEMU before calling 'trace_backend_init'?
> (as unlikely as it might be)
No, the guest is running at the BIOS prompt.
Stefan
- [Qemu-devel] [PATCH v11 0/7] trace: Generic event state description, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 1/7] trace: [tracetool] Explicitly identify public backends, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 2/7] trace: Provide a generic tracing event descriptor, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 3/7] trace: Provide a detailed event control interface, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 4/7] trace: [monitor] Use new event control interface, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 5/7] trace: [default] Port to generic event information and new control interface, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 6/7] trace: [simple] Port to generic event information and new control interface, Lluís Vilanova, 2013/03/01
- [Qemu-devel] [PATCH v11 7/7] trace: [stderr] Port to generic event information and new control interface, Lluís Vilanova, 2013/03/01
- Re: [Qemu-devel] [PATCH v11 0/7] trace: Generic event state description, Stefan Hajnoczi, 2013/03/04