Re: [RFC 02/11] perf/core: Data structure to present hazard data

[maddy]

On 3/2/20 3:25 PM, Peter Zijlstra wrote:
> On Mon, Mar 02, 2020 at 10:53:46AM +0530, Ravi Bangoria wrote:
> > From: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
> >
> > Introduce new perf sample_type PERF_SAMPLE_PIPELINE_HAZ to request kernel
> > to provide cpu pipeline hazard data. Also, introduce arch independent
> > structure 'perf_pipeline_haz_data' to pass hazard data to userspace. This
> > is generic structure and arch specific data needs to be converted to this
> > format.
> >
> > Signed-off-by: Madhavan Srinivasan <maddy@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxxxxxxxx>
> > ---
> >   include/linux/perf_event.h            |  7 ++++++
> >   include/uapi/linux/perf_event.h       | 32 ++++++++++++++++++++++++++-
> >   kernel/events/core.c                  |  6 +++++
> >   tools/include/uapi/linux/perf_event.h | 32 ++++++++++++++++++++++++++-
> >   4 files changed, 75 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> > index 547773f5894e..d5b606e3c57d 100644
> > --- a/include/linux/perf_event.h
> > +++ b/include/linux/perf_event.h
> > @@ -1001,6 +1001,7 @@ struct perf_sample_data {
> >   	u64				stack_user_size;
> >   
> >   	u64				phys_addr;
> > +	struct perf_pipeline_haz_data	pipeline_haz;
> >   } ____cacheline_aligned;
> >   
> >   /* default value for data source */
> > @@ -1021,6 +1022,12 @@ static inline void perf_sample_data_init(struct perf_sample_data *data,
> >   	data->weight = 0;
> >   	data->data_src.val = PERF_MEM_NA;
> >   	data->txn = 0;
> > +	data->pipeline_haz.itype = PERF_HAZ__ITYPE_NA;
> > +	data->pipeline_haz.icache = PERF_HAZ__ICACHE_NA;
> > +	data->pipeline_haz.hazard_stage = PERF_HAZ__PIPE_STAGE_NA;
> > +	data->pipeline_haz.hazard_reason = PERF_HAZ__HREASON_NA;
> > +	data->pipeline_haz.stall_stage = PERF_HAZ__PIPE_STAGE_NA;
> > +	data->pipeline_haz.stall_reason = PERF_HAZ__SREASON_NA;
> >   }
> NAK, Don't touch anything outside of the first cacheline here.

My bad, should have looked at the comment in "struct perf_sample_data {".
Will move it to perf_prepare_sample().

Thanks for comments.
Maddy