Re: [PATCH v1 3/7] perf cs-etm: Calculate per CPU metadata array size

Leo Yan
2021-01-16T00:52:07Z

Hi Mathieu,

On Fri, Jan 15, 2021 at 03:46:58PM -0700, Mathieu Poirier wrote:
> On Mon, Jan 11, 2021 at 12:09:12PM +0000, Mike Leach wrote:
> > Hi Leo,
> >
> > I think there is an issue here in that your modification assumes that
> > all cpus in the system are of the same ETM type. The original routine
> > allowed for differing ETM types, thus differing cpu ETM field lengths
> > between ETMv4 / ETMv3, the field size was used after the relevant
> > magic number for the cpu ETM was read.
> >
> > You have replaced two different sizes - with a single calculated size.
>
> I usually go through an entire patchset before looking at the comments people
> have made. In this case Mike and I are coming to the exact same conclusion.

Agreed, now this work depends on Mike's patch for extending metadata
version; otherwise if without Mike's patch, it will cause compability
issue.

> I will look at Mike's patch on Monday.

Cool!

Thanks for review,
Leo