lkml.org 
[lkml]   [2013]   [Apr]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH V2 5/5] powerpc, perf: Enable branch stack sampling framework support with BHRB
On 04/17/2013 05:37 PM, Anshuman Khandual wrote:
> 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@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.
>

Ahh, I remember it now. The function in the new file uses "cpu_hw_events" structure
which is passed during "record_and_restart" data capture phase. Right now cpu_hw_events is
not defined in the header file but inside core-book3s.c itself. Solution to this problem
could be any of these.

(0) Move all the code from the new file perf_event_bhrb.c into core-book3s.c
(1) Move cpu_hw_events structure to perf_event_server.h
(2) Create additional BHRB processing function inside struct power_pmu and
define it for P8 inside power8_pmu.c

Regards
Anshuman



\
 
 \ /
  Last update: 2013-04-18 05:21    [W:0.041 / U:0.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site