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| author |   Madhavan Srinivasan <maddy@linux.vnet.ibm.com> | 2017-07-25 11:05:51 +0530 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2017-08-10 22:30:04 +1000 |
| commit | 7aa345d84245a75760fc35a385fc5585f5e3336a (patch) | |
| tree | 999d0f85d249e863ad17b7a2430c521a0905c620 /arch | |
| parent | powerpc/44x/fsp2: Enable eMMC arasan for fsp2 platform (diff) | |
| download | linux-dev-7aa345d84245a75760fc35a385fc5585f5e3336a.tar.xz linux-dev-7aa345d84245a75760fc35a385fc5585f5e3336a.zip | |
powerpc/perf: Update default sdar_mode value for power9
Commit 20dd4c624d251 ('powerpc/perf: Fix SDAR_MODE value for continous
sampling on Power9') set the default sdar_mode value in MMCRA[SDAR_MODE]
to be used as 0b01 (Update on TLB miss). And this value is set if sdar_mode
from event is zero, or we are in continous sampling mode in power9 dd1.
But it is preferred to have the sdar_mode value for power9 as
0b10 (Update on dcache miss) for better sampling updates instead
of 0b01 (Update on TLB miss).
From Anton:
Using a bandwidth test case with a 1MB footprint, I profiled cycles and
chose TLB updates of the SDAR:
$ perf record -d -e r000400000000001E:u ./bw2001 1M
^
SDAR TLB
$ perf report -D | grep PERF_RECORD_SAMPLE | sed 's/.*addr: //' | sort -u | wc -l
4
I get 4 unique addresses. If I ran with dcache misses:
$ perf record -d -e r000800000000001E:u ./bw2001 1M
^
SDAR dcache miss
$ perf report -D|grep PERF_RECORD_SAMPLE| sed 's/.*addr: //'|sort -u | wc -l
5217
I get 5217 unique addresses. No surprises here, but it does show why
TLB misses is the wrong event to default to - we get very little useful
information out of it.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/perf/isa207-common.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/perf/isa207-common.h | 1 |
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c index 3f3aa9a7063a..582ed2c9bc56 100644 --- a/arch/powerpc/perf/isa207-common.c +++ b/arch/powerpc/perf/isa207-common.c @@ -99,7 +99,7 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra) else if (!cpu_has_feature(CPU_FTR_POWER9_DD1) && p9_SDAR_MODE(event)) *mmcra |= p9_SDAR_MODE(event) << MMCRA_SDAR_MODE_SHIFT; else - *mmcra |= MMCRA_SDAR_MODE_TLB; + *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..7a0228bf283c 100644 --- a/arch/powerpc/perf/isa207-common.h +++ b/arch/powerpc/perf/isa207-common.h @@ -247,6 +247,7 @@ #define MMCRA_SDAR_MODE_SHIFT 42 #define MMCRA_SDAR_MODE_TLB (1ull << MMCRA_SDAR_MODE_SHIFT) #define MMCRA_SDAR_MODE_NO_UPDATES ~(0x3ull << MMCRA_SDAR_MODE_SHIFT) +#define MMCRA_SDAR_MODE_DCACHE (2ull << MMCRA_SDAR_MODE_SHIFT) #define MMCRA_IFM_SHIFT 30 #define MMCRA_THR_CTR_MANT_SHIFT 19 #define MMCRA_THR_CTR_MANT_MASK 0x7Ful |