This patchset enables Nest Instrumentation support on powerpc.
POWER8 has per-chip Nest Intrumentation which provides various
per-chip metrics like memory, powerbus, Xlink and Alink
bandwidth.
Nest Instrumentation provides an interface (via PORE Engine)
to configure and move the nest counter data to memory. From
kernel side, OPAL Call interface is used to activate/deactivate
PORE Engine for nest data collection.
OPAL at boot, detects the feature, initializes it and pass on
the nest units and other related information such as memory
region, events supported so on, to kernel via device-tree.
Kernel code then, parses the device-tree for nest pmu supports
and registers nest pmu with the events available. PORE Engine collects
and accumulate nest counter data in per-chip HOMER region, hence
device-tree also exports per-chip HOMER nest accumulation region.
And individual event offset are used as event values.
Here is sample perf usage to explain the interface.
#./perf list
....
iTLB-load-misses [Hardware cache event]
Nest_Alink_BW/Alink0/ [Kernel PMU event]
Nest_Alink_BW/Alink1/ [Kernel PMU event]
Nest_Alink_BW/Alink2/ [Kernel PMU event]
Nest_MCS_Read_BW/MCS_00/ [Kernel PMU event]
Nest_MCS_Read_BW/MCS_01/ [Kernel PMU event]
Nest_MCS_Read_BW/MCS_02/ [Kernel PMU event]
Nest_MCS_Read_BW/MCS_03/ [Kernel PMU event]
Nest_MCS_Write_BW/MCS_00/ [Kernel PMU event]
Nest_MCS_Write_BW/MCS_01/ [Kernel PMU event]
Nest_MCS_Write_BW/MCS_02/ [Kernel PMU event]
Nest_MCS_Write_BW/MCS_03/ [Kernel PMU event]
Nest_PowerBus_BW/External/ [Kernel PMU event]
Nest_PowerBus_BW/Internal/ [Kernel PMU event]
Nest_Xlink_BW/Xlink0/ [Kernel PMU event]
Nest_Xlink_BW/Xlink1/ [Kernel PMU event]
Nest_Xlink_BW/Xlink2/ [Kernel PMU event]
rNNN [Raw hardware event
descriptor]
cpu/t1=v1[,t2=v2,t3 ...]/modifier [Raw hardware event
descriptor]
.....
# ./perf stat -e 'Nest_Xlink_BW/Xlink1/' -a -A sleep 1
Performance counter stats for 'system wide':
CPU0 15,913.18 MiB Nest_Xlink_BW/Xlink1/
CPU32 11,955.88 MiB Nest_Xlink_BW/Xlink1/
CPU64 11,042.43 MiB Nest_Xlink_BW/Xlink1/
CPU96 14,065.27 MiB Nest_Xlink_BW/Xlink1/
1.001062038 seconds time elapsed
# ./perf stat -e
'Nest_Alink_BW/Alink0/,Nest_Alink_BW/Alink1/,Nest_Alink_BW/Alink2/' -a -A -I
1000 sleep 5
Performance counter stats for 'system wide':
CPU0 0.00 MiB Nest_Alink_BW/Alink0/
(100.00%)
CPU32 0.00 MiB Nest_Alink_BW/Alink0/
(100.00%)
CPU64 0.00 MiB Nest_Alink_BW/Alink0/
(100.00%)
CPU96 0.00 MiB Nest_Alink_BW/Alink0/
(100.00%)
CPU0 1,430.43 MiB Nest_Alink_BW/Alink1/
(100.00%)
CPU32 320.99 MiB Nest_Alink_BW/Alink1/
(100.00%)
CPU64 3,443.83 MiB Nest_Alink_BW/Alink1/
(100.00%)
CPU96 1,904.41 MiB Nest_Alink_BW/Alink1/
(100.00%)
CPU0 2,856.85 MiB Nest_Alink_BW/Alink2/
CPU32 7.50 MiB Nest_Alink_BW/Alink2/
CPU64 4,034.29 MiB Nest_Alink_BW/Alink2/
CPU96 288.49 MiB Nest_Alink_BW/Alink2/
.....
OPAL side patches are posted in the skiboot mailing list.
Changelog from RFC:
1) Removed "uncore" code and made each Nest Unit a separate PMU.
2) Removed uncore type abstraction and uncore related functions.
3) Added simple cpumask function since these are per-chip counters
4) Redesigned device-tree parser based on the latest platform enablement code
5) Made changes to commit message
Kindly let me know you comments and feedback.
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com>
Cc: Stephane Eranian <eran...@google.com>
Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
Madhavan Srinivasan (9):
powerpc/powernv: Data structure and macros definition
powerpc/powernv: nest pmu init function with cpumask attr
powerpc/powernv: Add cpu hotplug support
powerpc/powernv: Add generic nest pmu ops
powerpc/powernv: nest pmu feature detection support
powerpc/powernv: dt parser function for nest pmu and its events
powerpc/powernv: Event attr creation and PMU registration
powerpc/powernv: Add OPAL support for Nest PMU
powerpc/powernv: Makefile changes to include nest pmu
arch/powerpc/include/asm/opal-api.h | 3 +-
arch/powerpc/include/asm/opal.h | 2 +
arch/powerpc/perf/Makefile | 2 +-
arch/powerpc/perf/nest-pmu.c | 489 +++++++++++++++++++++++++
arch/powerpc/perf/nest-pmu.h | 55 +++
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
6 files changed, 550 insertions(+), 2 deletions(-)
create mode 100644 arch/powerpc/perf/nest-pmu.c
create mode 100644 arch/powerpc/perf/nest-pmu.h
--
1.9.1
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