Re: [Qemu-devel] [PATCH 2/3] trace: enable tracing in qemu-io

[Eric Blake]

On 05/17/2016 02:20 AM, Denis V. Lunev wrote:
> Moving trace_init_backends() into trace_opt_parse() is not possible. This
> should be called after daemonize() in vl.c.
> 
> Signed-off-by: Denis V. Lunev <address@hidden>
> CC: Paolo Bonzini <address@hidden>
> CC: Stefan Hajnoczi <address@hidden>
> CC: Kevin Wolf <address@hidden>
> ---
>  qemu-io.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)

Please add documentation of the new syntax of the -T option, so that it
shows up in --help output (I'd ask for it in the man page, too, except
qemu-io doesn't seem to have one).

With just this patch applied, I still see in 'qemu-io --help':

  -T, --trace FILE     enable trace events listed in the given file

which doesn't tell me how to turn on particular trace events, vs. the
more useful details in 'qemu-system-x86_64 --help':

-trace [[enable=]<pattern>][,events=<file>][,file=<file>]
                specify tracing options

It is okay to just say "see qemu(1) man page for full description" (the
way we did for the --object option), rather than copy-and-paste a
paragraph that might go out of sync over time.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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