[PATCH v2 1/2] Documentation: perf: Update documentation for ThunderX2 PMU uncore driver
From: Ganapatrao Kulkarni
Date: Fri Jul 05 2019 - 05:14:21 EST
Add documentation for Cavium Coherent Processor Interconnect (CCPI2) PMU.
Signed-off-by: Ganapatrao Kulkarni <gkulkarni@xxxxxxxxxxx>
Documentation/perf/thunderx2-pmu.txt | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/Documentation/perf/thunderx2-pmu.txt b/Documentation/perf/thunderx2-pmu.txt
index dffc57143736..01315b3d4ad9 100644
@@ -2,24 +2,26 @@ Cavium ThunderX2 SoC Performance Monitoring Unit (PMU UNCORE)
The ThunderX2 SoC PMU consists of independent, system-wide, per-socket
-PMUs such as the Level 3 Cache (L3C) and DDR4 Memory Controller (DMC).
+PMUs such as the Level 3 Cache (L3C), DDR4 Memory Controller (DMC) and
+Cavium Coherent Processor Interconnect (CCPI2).
The DMC has 8 interleaved channels and the L3C has 16 interleaved tiles.
Events are counted for the default channel (i.e. channel 0) and prorated
to the total number of channels/tiles.
-The DMC and L3C support up to 4 counters. Counters are independently
-programmable and can be started and stopped individually. Each counter
-can be set to a different event. Counters are 32-bit and do not support
-an overflow interrupt; they are read every 2 seconds.
+The DMC and L3C support up to 4 counters, while the CCPI2 supports up to 8
+counters. Counters are independently programmable to different events and
+can be started and stopped individually. None of the counters support an
+overflow interrupt. DMC and L3C counters are 32-bit and read every 2 seconds.
+The CCPI2 counters are 64-bit and assumed not to overflow in normal operation.
PMU UNCORE (perf) driver:
The thunderx2_pmu driver registers per-socket perf PMUs for the DMC and
-L3C devices. Each PMU can be used to count up to 4 events
-simultaneously. The PMUs provide a description of their available events
-and configuration options under sysfs, see
-/sys/devices/uncore_<l3c_S/dmc_S/>; S is the socket id.
+L3C devices. Each PMU can be used to count up to 4 (DMC/L3C) or up to 8
+(CCPI2) events simultaneously. The PMUs provide a description of their
+available events and configuration options under sysfs, see
+/sys/devices/uncore_<l3c_S/dmc_S/ccpi2_S/>; S is the socket id.
The driver does not support sampling, therefore "perf record" will not
work. Per-task perf sessions are also not supported.