Visible to Intel only — GUID: GUID-274DDE84-C483-45A7-B10F-85BD30943EEB
Visible to Intel only — GUID: GUID-274DDE84-C483-45A7-B10F-85BD30943EEB
knob
Set configuration options for the specified analysis type or collector type.
GUI Equivalent
Configure Analysiswindow > HOW pane
Syntax
-knob | -k <knob-name>=<knob-value> |
Arguments
knob-name |
An analysis type or collector type may have one or more configuration options (knobs) that provide additional instructions for performing the specified type of analysis. To use a knob, you must specify the knob name and knob value. Multiple knob options are allowed and can be followed by additional action-options, as well as global-options, if needed. |
knob-value |
There are values available for each knob. In most cases this is a Boolean value, so for Boolean knobs, specify <knob-name>=true to enable the knob. |
Knob behavior may vary depending on the analysis type or collector type.
<knob-name> |
Description |
---|---|
accurate-cpu-time-detection=true | false (Windows only) Default: true |
Collect more accurate CPU time data. This option requires additional disk space and post-processing time. Administrator privileges are required. Supported analysis: runss |
analyze-loops=true | false Default: false |
Extend loop analysis to collect advanced loops information such as instruction set usage and display analysis results by loops and functions. Supported analysis: runss, runsa |
analyze-mem-objects=true | false Default: false |
Enable the instrumentation of memory allocation/de-allocation and map hardware events to memory objects. This option is supported only for Linux targets which run on the Intel microarchitectures code named Haswell (or newer). Supported analysis: memory-access |
analyze-openmp=true | false Default: true for the HPC Performance Characterization analysis; false for other analysis types. |
Instrument the OpenMP* runtimes in your application to group performance data by regions/work-sharing constructs and detect inefficiencies such as imbalance, lock contention, or overhead on performing scheduling, reduction, and atomic operations. Using this option may cause higher overhead and increase the result size. Supported analysis: hotspots, threading, hpc-performance, memory-access, uarch-exploration, runsa |
analyze-persistent-memory=true | false Default: false |
Collect performance information for Intel® Optane™ Persistent Memory modules. Supported analysis: platform-profiler |
analyze-power-usage=true | false Default: false |
Collect information about energy consumed by CPU, DRAM, and discrete GPU. Supported analysis: gpu-hotspots,gpu-offload |
analyze-throttling-reasons=true | false Default: false |
Collect information about factors that cause the CPU to throttle. Supported analysis: system-overview |
analyze-xelink-usage=true | false Default: false |
Collect information about data traffic between GPU interconnects (Xe Link) in multi-GPU analysis. Supported analysis: gpu-hotspots,gpu-offload |
atrace-config=<event> Available events are gfx, input, view, webview, wm, am, audio, video, camera, hal, res, dalvik. |
Collect Android framework events from Systrace*. Supported analysis: runsa |
characterization-mode=overview | global-local-accesses | compute-extended | full-compute | instruction-count Default: overview |
Monitor the Render and GPGPU engine usage (Intel Graphics only), identify which parts of the engine are loaded, and correlate GPU and CPU data. The Characterization mode uses platform-specific presets of the GPU metrics. All presets, except for the instruction-count, collect data about execution units (EUs) activity: EU Array Active, EU Array Stalled, EU Array Idle, Computing Threads Started, and Core Frequency; and each one introduces additional metrics:
Supported analysis: gpu-hotspots, graphics-rendering, runsa |
chipset-event-config="event1,event2 ,..." |
Specify a comma-separated list of Android chipset events (up to 5 events) to monitor with the hardware event-based sampling collector. Supported analysis: runsa |
source-analysis=bb-latency | mem-latency Default value: bb-latency |
Collect data on performance-critical basic blocks and issues caused by memory accesses in the GPU kernels. Choose one of the following modes:
Supported analysis: gpu-hotspots |
collect-bad-speculation=true | false Default value: true |
Collect the minimum set of data required to compute top-level metrics and all Bad Speculation sub-metrics. Supported analysis: uarch-exploration, runsa |
collect-core-bound=true | false Default: false |
Collect the minimum set of data required to compute top-level metrics and all Core Bound sub-metrics. Supported analysis: uarch-exploration, runsa |
collect-frontend-bound=true | false Default value: true |
Collect the minimum set of data required to compute top-level metrics and all Front-End Bound sub-metrics. Supported analysis: uarch-exploration, runsa |
collect-cpu-gpu-bandwidth=true | false Default: false |
Collect DRAM bandwidth data for all hosts. Additionally, collect PCIe bandwidth for supported server hosts (Intel® micro-architectures code named Ice Lake and Sapphire Rapids). To view collected data in GUI, enable the Analyze CPU host-GPU bandwidth option. Supported analysis:gpu-offload |
collect-cpu-gpu-pci-bandwidth=true | false Default: false |
Collect PCIe bandwidth for supported server hosts (Intel® micro-architectures code named Ice Lake and Sapphire Rapids). This knob is available for custom analyses only. To view collected data in GUI, enable the Analyze CPU host-GPU bandwidth option. Supported analysis:runsa |
collect-io-waits=true | false Default: false |
Analyze the percentage of time each thread and CPU spends in I/O wait state. Supported analysis: runsa |
collect-memory-bandwidth=true | false Default: depends on analysis type |
Collect data to identify where your application is generating significant bandwidth to DRAM. To view collected data in GUI, enable the Analyze memory bandwidth option. Supported analysis: performance-snapshot, uarch-exploration, hpc-performance, gpu-hotspots,runsa |
collect-memory-bound=true | false Default value: true |
Collect the minimum set of data required to compute top-level metrics and all Memory Bound sub-metrics. Supported analysis: uarch-exploration, hpc-performance |
collect-programming-api=true | false Default for gpu-hotspots: true, for runss: false. |
Analyze execution of SYCL apps, OpenCL™ kernels and Intel® Media SDK programs on Intel HD Graphics and Intel® Iris® Graphics. This option may affect the performance of your application on the CPU side. Supported analysis: gpu-hotspots, gpu-offload, runsa |
collect-retiring=true | false Default value: true |
Collect the minimum set of data required to compute top-level metrics and all Retiring sub-metrics. Supported analysis: uarch-exploration, runsa |
collecting-mode=hw-tracing | hw-tracing Default value: hw-sampling |
Specify the system-wide collection mode to either explore CPU, GPU, and I/O resources utilization with the default event-based sampling mode, or enable the low-overhead hardware tracing and identify a root cause of latency issues. Supported analysis: system-overview, runsa |
computing-tasks-of-interest=computing_task_name[#start_idx#step#stop_idx] |
Specify a comma-separated list of GPU computing task names and invocations. Use a search string, if necessary (* and . are supported). On Windows OS, Intel® VTune™ Profiler does not demangle C++ kernel names during runtime. Instead of searching for the exact C++ kernel name(s), use the search string. For example, when you set -knob computing-tasks-of-interest=gemm#1#1#4294967295, the search covers all kernels in the source code which have gemm in their name. Invocations happen in this format: computing_task_name[#start_idx#step#stop_idx] Default value:*#1#1#4294967295
Supported analysis: gpu-hotspots, runsa |
counting-mode=true | false Default: false |
Choose between collecting detailed context data for each PMU event (such as code or hardware context) or the counts of events. Counting mode introduces less overhead but gives less information. Supported analysis: runsa |
cpu-samples-mode=off | stack | nostack Default: false |
Enable to periodically sample the application. Samples can be collected with or without stacks. Supported analysis: runss |
dpdk=true | false Default: false |
Profile DPDK IO API. Supported analysis: io |
dram-bandwidth-limits=true | false Default: true for the HPC Performance Characterization and Microarchitecture Exploration analysis with collect-memory-bandwidth knob enabled; true for the Memory Access and Microarchitecture Exploration analysis. |
Evaluate maximum achievable local DRAM bandwidth before the collection starts. This data is used to scale bandwidth metrics on the timeline and calculate thresholds. Supported analysis: performance-snapshot, memory-access, uarch- exploration, hpc-performance, runsa |
enable-characterization-insights=true | false |
Get additional performance insights such as the efficiency of hardware usage, and learn next steps. Supported analysis: gpu-offload |
enable-context-switches=true | false Default: false |
Analyze detailed scheduling layout for all threads in your application, explore time spent on a context switch and identify the nature of context switches for a thread (preemption or synchronization). Supported analysis: runsa |
enable-driverless-collection=true | false Default: false |
Enable driverless Linux Perf collection when possible. Supported analysis: runsa |
enable-gpu-usage=true | false Default: false |
Analyze frame rate and usage of Intel HD Graphics and Intel® Iris® Graphics engines and identify whether your application is GPU or CPU bound. Supported analysis: runss, runsa |
enable-interrupt-collection=true | false Default: false |
Collect interrupt events that alter a normal execution flow of a program. Such events can be generated by hardware devices or by CPUs. Use this data to identify slow interrupts that affect your code performance. Supported analysis: system-overview. |
enable-parallel-fs-collection=true | false Default: false |
Analyze Lustre* file system performance statistics, including Bandwidth, Package Rate, Average Packet Size, and others. Supported analysis: runsa |
enable-stack-collection=true | false Default: false |
Enable Hardware Event-based Sampling Collection with Stacks. Supported analysis: hotspots, hpc-performance, gpu-offload, runsa |
enable-system-cswitch=true | false Default: false |
Analyze detailed scheduling layout for all threads on the system and identify the nature of context switches for a thread (preemption or synchronization). Supported analysis: runsa |
enable-thread-affinity=true | false Default: false |
Analyze thread pinning to sockets, physical cores, and logical cores. Identify incorrect affinity that utilizes logical cores instead of physical cores and contributes to poor physical CPU utilization.
NOTE:
Affinity information is collected at the end of the thread lifetime, so the resulting data may not show the whole issue for dynamic affinity that is changed during the thread lifetime. |
enable-user-sync=true | false Default: false |
Collect synchronization data via the User-Defined Synchronization API. Supported analysis: threading, runss |
enable-user-tasks=true | false Default: false |
Analyze tasks, events and counters specified in your application via the Task API. This option causes higher overhead and increases result size. Supported analysis: hotspots, threading, uarch-exploration, runss, runsa |
event-config=<event_name1>,<event_name2>,... |
Configure PMU events to collect with the hardware event-based sampling collector. Multiple events can be specified as a comma-separated list (no spaces).
NOTE:
To display a list of events available on the target PMU, enter: vtune -collect-with runsa -knob event-config=? <target> The command returns names and short descriptions of available events. For more information on the events, use Intel Processor Events Reference. Supported analysis: runsa |
event-mode=all | user | os Default: all |
Limit event-based sampling collection to OS or USER mode. Supported analysis: runsa |
ftrace-config=<event_name> Available events are freq, idle, sched, disk, filesystem, irq, kvm, workq, softirq, sync. Default for Linux targets: sched,freq,idle,workq,irq,softirq Default for Android targets: sched,freq,idle,workq,filesystem, irq,softirq,sync,disk |
Collect Linux Ftrace* framework events.
Supported analysis: runsa, runss |
gpu-sampling-interval=<number> between 0.1 and 1000ms Default: 1. |
Specify an interval between GPU samples (in milliseconds). Supported analysis: gpu-hotspots, graphics-rendering, runss, runsa |
io-mode=off | stack | nostack Default: off |
Enable to identify where threads are waiting or compute thread concurrency. The collector instruments APIs, which causes higher overhead and increases result size. Supported analysis: runss, runsa |
ipt-regions-to-load=<number> between 10 and 5000 Default: 1000 |
Specify the maximum number (10-5000) of code regions to load for detailed analysis. Supported analysis: anomaly-detection |
kernel-stack=true | false Default: true |
Profile system disk IO API. Supported analysis: io |
max-region-duration=<number> between 0.001 and 1000 ms Default: 100 |
Specify the maximum duration (0.001-1000ms) of analysis per code region. Supported analysis: anomaly-detection |
mem-object-size-min-thres=<number> Default: 1024 bytes |
Specify a minimal size of memory allocations to analyze. This option helps reduce runtime overhead of the instrumentation. This option is supported only for Linux targets which run on Intel microarchitectures code named Haswell (or later). Supported analysis: memory-access |
metrics_set=NOC Default: NOC |
Specify the type of metrics set to collect. Supported analysis: npu |
mrte-type=java,dotnet | java,dotnet,python | python Default: java,dotnet |
Specify a type of managed runtime to analyze. Available values: combined .NET* and Java* analysis, combined Java, .NET and Python* analysis, and Python only. Supported analysis: runss, runsa |
no-altstack=true | false Default: false |
Disable using alternative stacks for signal handlers. Consider this option for profiling standard Python 3 code on Linux. Supported analysis: runss |
pmu-collection-mode=detailed | summary Default: detailed |
Choose the detailed sampling-based collection mode to view data breakdown per function and other hotspots. Use the summary counting-based mode for an overview of the whole profiling run. This mode has a lower collection overhead and fast post-processing time. Supported analysis: uarch-exploration |
profiling-mode=characterization (default), code-level-analysis, query-based, time-based |
Select a profiling mode for these analyses:
Supported analysis: gpu-hotspots, runsa, npu |
sampling-interval=<number> For user-mode sampling and tracing types: a number (in milliseconds) between 1 and 1000. Default: 10 For hardware event-based sampling types: a number (in milliseconds) between 0.01 and 1000. Default: 1. For NPU exploration: a number (in milliseconds) between 0.1 and 1000. |
Specify a sampling interval (in milliseconds) between CPU samples. For NPU Exploration analysis, specify the sampling interval for data collection in time-based mode. Supported analysis: hotspots,runss, threading, ,runsa, system-overview, memory-access, hpc-performance, npu |
sampling-mode=sw | hw Default: sw |
Specify a profiling mode. Use sw to identify CPU hotspots and explore a call flow of your program. This mode does not require sampling drivers to be installed but incurs more collection overhead. Use hw to identify application hotspots based on such basic hardware events as Clockticks and Instructions Retired. This is a low-overhead collection mode but it requires the sampling driver to be installed on your system. Supported analysis: hotspots, threading |
signals-mode=off | objects | stack | nostack Default: off |
Enable to view synchronization transitions in the timeline and signalling call stacks for associated waits. The collector instruments signalling APIs, which causes higher overhead and increases result size. Supported analysis: runss |
spdk=true | false Default: false |
Profile SPDK IO API. Supported analysis: io |
stack-size=<number> A number between 0 and 2147483647. Default is 0 (unlimited stack size). |
Reduce the collection overhead and limit the stack size (in bytes) processed by the VTune Profiler. Supported analysis: runsa |
stack-stitching=true | false Default: true |
For Intel® oneAPI Threading Building Blocks(oneTBB )-based applications, restructure the call flow to attach stacks to a point introducing a parallel workload. Supported analysis: runss |
stack-type=software | lbr Default: software |
Choose between software stack and hardware LBR-based stack types. Software stacks have no depth limitations and provide more data while hardware stacks introduce less overhead. Typically, software stack type is recommended unless the collection overhead becomes significant. Note that hardware LBR stack type may not be available on all platforms. Supported analysis: runsa |
stackwalk-mode=online | offline Default: offline |
Choose between online (during collection) and offline (after collection) modes to analyze stacks. Offline mode reduces analysis overhead and is typically recommended. Supported analysis: runss |
target-gpu= <domain:bus:device.function[:stack]> Default: All GPU devices |
Select at least one target GPU adapter or stack to collect GPU profiling data. If unset, VTune Profiler collects profiling data for all stacks of all GPUs. If you select a device and do not specify a stack, VTune Profiler collects data for all stacks of the device. Example: target-gpu=0:58:0.0:1,0:154:0.0 Supported analysis: gpu-offload, gpu-hotspots |
uncore-sampling-interval=<number> For hardware event-based sampling types: a number (in milliseconds) between 1 and 1000. Default: 10. |
Specify an interval (in milliseconds) between uncore event samples. Supported analysis: runsa |
waits-mode=off | stack | nostack Default: off |
Enable to identify where threads are waiting or compute thread concurrency. The collector instruments APIs, which causes higher overhead and increases result size. Supported analysis: runss |
Actions Modified
Description
Use the knob action-option to configure knob settings for a collect (predefined analysis types) or collect-with (custom analysis types) action where the analysis type supports one or more knobs. Each analysis type or collector type supports a specific set of knobs, and each knob requires a value. In most cases the knob value is Boolean, so you would use True to enable the knob.
To see all knobs available for a predefined analysis type:
vtune -help collect <analysis_type>
To see knobs for a custom analysis type:
vtune -help collect-with <analysis_type>
Example
This example returns a list of knobs for the Threading analysis type:
vtune -help collect threading
This example runs a custom event-based sampling data collection on an Android system enabling collection of Android framework and chipset events.
vtune -collect-with runss -target-system=android -knob sampling-interval=2 -knob cpu-samples-mode=stack -knob ftrace-config=gfx,dalvik -knob chipset-event-config="GMCH_PARTIAL_WR_DRAM.ANY,GMCH_CORE_CLKS" --target-process com.intel.tbb.example.tachyon
This example configures and runs a custom event-based sampling data collection with the stack size limited to 8192 bytes:
vtune -collect-with runsa -knob enable-stack-collection=true -knob stack-size=8192 -knob enable-call-counts=true -knob event-config=CPU_CLK_UNHALTED.REF_TSC:sa=1800000,CPU_CLK_UNHALTED