[PATCH v2 0/7]powerpc/powernv: Nest Instrumentation support
Madhavan Srinivasan
maddy at linux.vnet.ibm.com
Thu Jun 11 15:17:47 AEST 2015
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 support
and registers nest pmu with the events available. PORE Engine collects
and accumulate nest counter data in per-chip reserved memory region, hence
device-tree also exports per-chip nest accumulation memory region.
And individual event offset are used as event configuration 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 v1:
1) No logic changes, re-ordered patches make each patch compile
without errors
2) Added comments based on the review feedback.
3) removed perf_event_del function and replaced it with perf_event_stop.
4) Moved Nest feature detection code out of parser function.
5) Optimized functions and removed some variables.
6) squashed the makefile changes, instead of the separate patch
7) squashed the cpumask and hotplug patches as single patch
8) Added cpu checks in nest_change_cpu_context and nest_exit_cpu functions
9) Made changes to commit messages.
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
Thanks to intput from Daniel Axtens, Suzuki Poulose and Michael Ellerman
Kindly let me know you comments and feedback.
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Cc: Paul Mackerras <paulus at samba.org>
Cc: Anton Blanchard <anton at samba.org>
Cc: Sukadev Bhattiprolu <sukadev at linux.vnet.ibm.com>
Cc: Anshuman Khandual <khandual at linux.vnet.ibm.com>
Cc: Stephane Eranian <eranian at google.com>
Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
Madhavan Srinivasan (7):
powerpc/powernv: Data structure and macros definition
powerpc/powernv: Add OPAL support for Nest PMU
powerpc/powernv: Nest PMU detection and device tree parser
powerpc/powernv: detect supported nest pmus and its events
powerpc/powernv: add event attribute and group to nest pmu
powerpc/powernv: generic nest pmu event functions
powerpc/powernv: nest pmu cpumask and cpu hotplug support
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 | 520 +++++++++++++++++++++++++
arch/powerpc/perf/nest-pmu.h | 53 +++
arch/powerpc/platforms/powernv/opal-wrappers.S | 1 +
6 files changed, 579 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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