Re: [PULL 10/11] trace: document how to specify multiple --trace patterns

[Stefan Hajnoczi]

On Mon, Feb 01, 2021 at 07:13:27PM +0100, BALATON Zoltan wrote:
> On Mon, 1 Feb 2021, Daniel P. Berrangé wrote:
> > On Mon, Feb 01, 2021 at 06:25:33PM +0100, Paolo Bonzini wrote:
> > > On 01/02/21 17:54, Kevin Wolf wrote:
> > > > > How does this option parsing work? Would then multiple patterns 
> > > > > separated by
> > > > > comma as in -trace pattern1,pattern2 also work?
> > > > This would be interpreted as an implied "enable" option with a value of
> > > > "pattern1,pattern2". I don't think anything splits that string at the
> > > > comma, so it would look for a trace event matching that string.
> > > 
> > > Even worse, it would be interpreted as "-trace 
> > > enable=pattern1,pattern2=on"
> > > (and raise a warning since recently).
> > 
> > Maybe we're trying to solve the problem at the wrong level.
> 
> There's no problem to solve, just trying to understand better what are the
> valid options. It's already possible to enable multiple patterns with either
> events=file or repeating -trace options (with or without enable=) so that's
> already sufficient, I was just curious what other options are there and if
> there's a simpler way that we could document. If not, using the current ways
> that are now documented is OK I think.

The enable=PATTERN syntax is very limited. Repeating the --trace option
is currently the only way to enter multiple patterns on the
command-line.

Stefan

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