LatencyMon has been analyzing your system for 13:31:28 (h:mm:ss) on all processors. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. You may experience drop outs, clicks or pops due to buffer underruns. powerpc/cpuidle_latency/settings | 1 +Ĭreate mode 100644 arch/powerpc/kernel/test-cpuidle_latency.cĬreate mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/.gitignoreĬreate mode 100644 tools/testing/selftests/powerpc/cpuidle_latency/MakefileĬreate mode 100755 tools/testing/selftests/powerpc/cpuidle_latency/cpuidle_latency.Your system seems to be having difficulty handling real-time audio and other tasks. powerpc/cpuidle_latency/.gitignore | 2 + Tools/testing/selftests/powerpc/Makefile | 1 + Powerpc/selftest: Add support for cpuidle latency measurementĪrch/powerpc/kernel/test-cpuidle_latency.c | 157 +++++++ Powerpc/cpuidle: Extract IPI based and timer based wakeup latency from # Observed Average timeout diff(ns) - Stop5: 939977 # Observed Average timeout diff(ns) - Stop4: 16581 # Observed Average timeout diff(ns) - Stop2: 1845 # Observed Average timeout diff(ns) - Stop0: 1715 # Observed Average timeout diff(ns) - Stop0_lite: 1764 # Observed Average timeout diff(ns) - Snooze: 1640 # Baseline Average timeout diff(ns): 1420 # Observed Average IPI latency(ns) - Stop5: 1038174

# Observed Average IPI latency(ns) - Stop4: 17070 # Observed Average IPI latency(ns) - Stop2: 3807 # Observed Average IPI latency(ns) - Stop0: 3739 # Observed Average IPI latency(ns) - Stop0_lite: 3507 # Observed Average IPI latency(ns) - Snooze: 3265 Sample output on a POWER9 system is as follows: Timeout_diff_ns = Difference of actual duration vs expected timer Timeout_cpu_src = CPU on which the timer to be queued Ipi_latency_ns = Measured latency time in ns Ipi_cpu_dest = Destination CPU for the IPI The kernel module provides the following interfaces within Knobs through the debugfs interface that the selftests can engage with. To achieve this, we introduce a kernel module and expose its control

Program also measures a baseline latency on a 100 percent loaded CPUĪnd the latencies achieved must be in view relative to that. The kernel-firmware-hardware interactions. IPIs and TimersĪs this is a software-only mechanism, there will additional latencies of The patchset measures latencies for two kinds of events. To find significant deviations behind advertised latency and residency A kernel module + userspace driver to estimate the wakeup latencyĬaused by going into stop states.

Kernel mode driver framework latency