[PATCH] powerpc/perf: Fix SDAR_MODE value for continous sampling in power9

[PATCH] powerpc/perf: Fix SDAR_MODE value for continous sampling in power9

[Madhavan Srinivasan]

Incase of continous sampling, code currently defaults
MMCRA[SDAR_MODE] to 0b01 for power9 DD1 which is
'Continous sampling mode update SDAR on TLB miss'.
And for the rest it copies the sdar_mode value from
the event code, which mostly turns out to be 0b00
('No Updates').

Instead, fix the sdar_mode to 0b10
('Continous sampling mode update SDAR on dcache miss')
as default for power9 incase of continous sampling.

Fixes: 78b4416aa2493 ('powerpc/perf: Handle sdar_mode for marked event in power9')
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
---
 arch/powerpc/perf/isa207-common.c | 8 +++++---
 arch/powerpc/perf/isa207-common.h | 1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 8125160be7bc..ae0cd2a29e68 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -90,14 +90,16 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra)
 	 *	MMCRA[SDAR_MODE] will be set to 0b01
 	 * For rest
 	 *	MMCRA[SDAR_MODE] will be set from event code.
+	 *      If sdar_mode from raw code is zero, default to 0b10.
 	 */
 	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
 		if (is_event_marked(event) || (*mmcra & MMCRA_SAMPLE_ENABLE))
 			*mmcra &= MMCRA_SDAR_MODE_NO_UPDATES;
-		else if (!cpu_has_feature(CPU_FTR_POWER9_DD1))
+		else if ((!cpu_has_feature(CPU_FTR_POWER9_DD1) &&
+							p9_SDAR_MODE(event)))
 			*mmcra |=  p9_SDAR_MODE(event) << MMCRA_SDAR_MODE_SHIFT;
-		else if (cpu_has_feature(CPU_FTR_POWER9_DD1))
-			*mmcra |= MMCRA_SDAR_MODE_TLB;
+		else
+			*mmcra |= MMCRA_SDAR_MODE_DCACHE;
 	} else
 		*mmcra |= MMCRA_SDAR_MODE_TLB;
 }
diff --git a/arch/powerpc/perf/isa207-common.h b/arch/powerpc/perf/isa207-common.h
index 8acbe6e802c7..250d91f4d642 100644
--- a/arch/powerpc/perf/isa207-common.h
+++ b/arch/powerpc/perf/isa207-common.h
@@ -246,6 +246,7 @@
 #define MMCRA_THR_CMP_SHIFT		32
 #define MMCRA_SDAR_MODE_SHIFT		42
 #define MMCRA_SDAR_MODE_TLB		(1ull << MMCRA_SDAR_MODE_SHIFT)
+#define MMCRA_SDAR_MODE_DCACHE		(2ull << MMCRA_SDAR_MODE_SHIFT)
 #define MMCRA_SDAR_MODE_NO_UPDATES	~(0x3ull << MMCRA_SDAR_MODE_SHIFT)
 #define MMCRA_IFM_SHIFT			30
 #define MMCRA_THR_CTR_MANT_SHIFT	19
-- 
2.7.4

Re: powerpc/perf: Fix SDAR_MODE value for continous sampling in power9

[Michael Ellerman]

On Tue, 2017-07-11 at 10:57:49 UTC, Madhavan Srinivasan wrote:
> Incase of continous sampling, code currently defaults
> MMCRA[SDAR_MODE] to 0b01 for power9 DD1 which is
> 'Continous sampling mode update SDAR on TLB miss'.
> And for the rest it copies the sdar_mode value from
> the event code, which mostly turns out to be 0b00
> ('No Updates').
> 
> Instead, fix the sdar_mode to 0b10
> ('Continous sampling mode update SDAR on dcache miss')
> as default for power9 incase of continous sampling.
> 
> Fixes: 78b4416aa2493 ('powerpc/perf: Handle sdar_mode for marked event in power9')
> Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/20dd4c624d25156d5ec3345bbb690b

cheers