Threads view reports in the Concurrency Visualizer
This article provides information about the reports in the Threads view of the Concurrency Visualizer.
Blocking time profile report
The Profile Reports provide aggregate blocking time data for call stacks that are specific to each blocking category (for example "I/O" or "Synchronization"). The Preemption report lists the processes that preempted the current process together with the number of preemption instances. To build the blocking profile report, the tool collects blocking API calls and accumulates them into a tree of call stacks. Data that's shown in these reports varies by the current time range, by hidden threads, and by the following two filters that may be applied:
If Just My Code is selected, only stack frames that have user code are presented, plus one level below the user code.
If the Noise reduction value is set, collated stacks that have less than the specified frequency are skipped.
Expand any call-tree entry to find the line of code in which blocking time is spent. To locate the line of source for an entry, on its shortcut menu, choose View Source. To locate the line of code that called this one, on the shortcut menu, choose View Call Sites. If only one call site is available, the command connects to the highlighted line of code for the call site. If multiple call sites are available, the command opens a dialog box in which you can select an entry and then choose the Go to source button to locate the highlighted call site. It's often most useful to view source code for the call site that has the most instances, the most time, or both.
Blocking time report columns
The following table shows the columns for each blocking time report.
| Column name | Description |
|---|---|
| Name | The name of the function for each level of the call stack. |
| Instances | The number of instances of the blocking call for the visible time period. |
| Inclusive Blocking Time | The total blocking time that's spent for all stacks that roll up to this level of the call stack tree. The inclusive number is the sum of exclusive blocking time for this function and exclusive blocking time for all its child nodes. |
| Exclusive Blocking Time | The total blocking time that's spent during which this function is the lowest level of the call stack. A unique call stack entry that has a high exclusive blocking time may be a function of interest. |
| API/Wait Category | Shown only for functions at the lowest level of the call stack. Where the signature of the blocking call is recognized, the name of the blocking API is provided. If the signature is not recognized, the information that's reported by the kernel is provided. |
| Details | Fully qualified name of the function. This includes line count when it's available. |
Synchronization
The Synchronization report shows the calls that are responsible for segments that are blocking on synchronization, and the aggregate blocking times of each call stack. For more information, see Synchronization time.
Sleep
The Sleep report shows the calls that are responsible for blocking time that was attributed to time that was spent sleeping, and the aggregate blocking times of each call stack. For more information, see Sleep time.
I/O
The I/O report shows the calls that are responsible for segments that are blocking on I/O, and the aggregate blocking times of each call stack. For more information, see I/O time (threads view).
Memory management
The Memory Management report shows the calls that are responsible for segments that are blocking on memory management operations, and the aggregate blocking times of each call stack. For more information, see Memory management time.
Preemption
The Preemption report lists the processes that preempted the current process together with the number of instances. You can expand each process to view the specific threads that replaced threads in the current process and to view a breakdown of preemption instances per thread. This blocking report is less actionable than the others because preemption is typically imposed on your process by the operating system, not by a problem in your code. For more information, see Preemption time.
UI processing
The UI Processing report shows the calls that are responsible for blocking segments that are blocking on UI processing blocks, and the aggregate blocking times of each call stack. For more information, see UI processing time.
Disk Operations Report (Threads View)
The Disk Operations Report shows disk I/O operations in the disk channels.
For each disk access that occurs on behalf of the process that's being profiled in the currently visible time window, this information is reported:
The name and PID of the process that performed the disk access
The ID of the thread that accessed the disk
The name of the file that was accessed
The number of reads per file
The number of bytes read
The read latency, in milliseconds
The number of writes
The number of bytes written
The write latency, in milliseconds
Execution Profile Report
The Execution Profile Report is a traditional sampling profile. Samples are taken approximately every millisecond during periods when a thread is running on a logical core, and the Concurrency Visualizer builds a typical call tree by collating the accumulated set of sample stacks. Data in this table can be affected by the current time range and hidden threads, and by these filters that may be applied:
If Just My Code is selected, only stack frames that have user code, plus one level below the user code, are shown.
If the Noise reduction value is set, collated stacks that have less than the specified frequency are filtered out of the report
The following table shows columns in the report.
| Column | Description |
|---|---|
| Name | The name of the function for each level of the call stack. |
| Inclusive samples | Total number of samples that are collected for all stacks that roll up into this level of the call stack tree. The inclusive number is the sum of exclusive samples for this function and inclusive counters for all its child nodes. |
| Exclusive Samples | Total number of collected samples for which this function is the lowest level of the call stack. |
| % Inclusive | The percentage of total samples that is shown in the inclusive samples column. Percentages are rounded to two decimal places. |
| % Exclusive | The percentage of total samples that is shown in the exclusive samples column. Percentages are rounded to two decimal places. |
| Details | Fully qualified name of the function. This includes line count when it is available. |
This report table can be seen in the Execution time (Threads View) view.
Markers Report
The Markers Report lists the markers in the displayed time frame. Panning or zooming, or hiding lanes, might cause markers to appear or disappear. The report contains this information about each marker:
The time when it began, relative to the start of the trace.
Its duration. The duration is zero for flags and messages because they represent an instant.
The ID of the thread that generated it.
The Event Tracking for Windows (ETW) provider that generated it.
The marker series from which it was written.
The category of events it belongs to.
Its importance level.
Its type (span, flag, or message).
A high-level description of what it represents
Choose the Export button to save the Markers Report as a CSV file. You can use the data in the CSV file with other apps or tools.
Note
The Markers Report can display 1,000 markers. To see all markers, export the full report to a CSV file.
Per thread summary report
This bar graph shows the proportion of time each unhidden thread spends in each activity category during the currently visible time range. "Execution" means that the thread is executing; all other categories mean that the thread is waiting for something.