[PATCH V2 5/5] powerpc, perf: Enable branch stack sampling framework support with BHRB

Anshuman Khandual khandual at linux.vnet.ibm.com
Wed Apr 17 22:07:50 EST 2013


On 04/17/2013 12:38 PM, Michael Ellerman wrote:
> On Tue, Apr 16, 2013 at 09:24:10PM +0530, Anshuman Khandual wrote:
>> This patch provides basic enablement for perf branch stack sampling framework
>> on POWER8 processor with a new PMU feature called BHRB (Branch History Rolling
>> Buffer).
>>
>> Signed-off-by: Anshuman Khandual <khandual at linux.vnet.ibm.com>
>> ---
>>  arch/powerpc/perf/core-book3s.c     | 96 +++++++++++++++++++++++++++++++++++--
>>  arch/powerpc/perf/perf_event_bhrb.c | 85 ++++++++++++++++++++++++++++++++
>>  2 files changed, 178 insertions(+), 3 deletions(-)
>>  create mode 100644 arch/powerpc/perf/perf_event_bhrb.c
>>
>> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
>> index 4ac6e64..f4d1347 100644
>> --- a/arch/powerpc/perf/core-book3s.c
>> +++ b/arch/powerpc/perf/core-book3s.c
>> @@ -19,6 +19,8 @@
>>  #include <asm/firmware.h>
>>  #include <asm/ptrace.h>
>>  
>> +#define BHRB_MAX_ENTRIES	32
>> +
>>  struct cpu_hw_events {
>>  	int n_events;
>>  	int n_percpu;
>> @@ -38,11 +40,21 @@ struct cpu_hw_events {
>>  
>>  	unsigned int group_flag;
>>  	int n_txn_start;
>> +
>> +	/* BHRB bits */
>> +	u64				bhrb_filter;	/* BHRB HW branch filter */
>> +	int				bhrb_users;
>> +	void				*bhrb_context;
>> +	struct	perf_branch_stack	bhrb_stack;
>> +	struct	perf_branch_entry	bhrb_entries[BHRB_MAX_ENTRIES];
>>  };
>> +
>>  DEFINE_PER_CPU(struct cpu_hw_events, cpu_hw_events);
>>  
>>  struct power_pmu *ppmu;
>>  
>> +#include "perf_event_bhrb.c"
>> +
> 
> Um, why are you doing that?
> 

There was no specific reason for that.

> If it's code that should be in a header, put it in a header. If it's C
> code, add it to the Makefile.

Sure I would get the new code in the Makefile. Thanks!

Regards
Anshuman

> 
> cheers
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