Re: [RFC PATCH 0/3]perf/core: extend perf_reg and perf_sample_regs_intr

On Thursday 05 November 2015 06:37 PM, Peter Zijlstra wrote:

On Thu, Nov 05, 2015 at 02:16:15AM +0530, Madhavan Srinivasan wrote:

quoted

Second patch updates struct arch_misc_reg for arch/powerpc with pmu registers
and adds offsetof macro for the same. It extends perf_reg_value()
to use reg idx to decide on struct to return value from.

Why; what's in those regs?

Was out and did not have access to mail, so missed to respond in time.

In current implementation of patch 2, have added 
few pmu control/status and counter registers,
which give additional information about the PMU context
for the sample.

These pmu registers are not relevant for ptrace and did not
want to overload pt_regs struct.

Adding these arch specific regs in perf_regs will break the "arch
neutral" part, and
other arch can also use this new struct in perf_regs to add more data
using perf_sample_regs_intr without extending the pt_regs.

Maddy