Re: [PATCH 1/4] perf vendor events: Syntax corrections in Neoverse N1 json

[Andi Kleen]

On 10/6/2021 9:26 AM, John Garry wrote:
> On 06/10/2021 09:43, James Clark wrote:
>
> + Andi
>
> > On 05/10/2021 11:10, John Garry wrote:
> > > On 04/10/2021 17:00, Andrew Kilroy wrote:
> > > > There are some syntactical mistakes in the json files for the 
> > > > Cortex A76
> > > > N1 (Neoverse N1).  This was obstructing parsing from an external tool.
> > >
> > > If the trailing comma is not allowed by standard, then maybe we 
> > > should fix our parsing tool to not allow it also. However maybe 
> > > there is a good reason why we allow it..
> >
> > It would be nice to do, because I have also made similar fixes 
> > before. We looked at the STRICT option
> > in the parser (https://github.com/zserge/jsmn), but even then it 
> > seems to allow trailing commas.
> >
> > Trailing commas are not allowed in the json standard, but there is a 
> > split between parsers
> > where some allow it and others don't. Specifically the Python parser 
> > doesn't allow it, and Python
> > can easily be involved in some workflow that parses these files.
> >
> > The only way forwards I can think of is either getting a change 
> > accepted upstream to the parser
> > and then updating it in perf, switching to a different parser, or 
> > doing some hack to add an extra
> > step in perf to look for commas. None of which sound ideal.
>
> Looking at the license in jsmn.c, we seem to be ok to modify it (to 
> error on non-standard trailing ',') - that parser has already 
> apparently been modified in mainline.
>
> If we do that then I hope that there are not to many violations in out 
> JSONs, including downstream.


Sure we can modify the file. I already did some minor changes when I 
submitted it originally.

-Andi