Synchronization Time

These segments in the timeline are associated with blocking times that are categorized as Synchronization. When a thread is marked as blocked on synchronization, one of these things is implied:

  • The execution of the thread may have resulted in a call to a well-known thread synchronization API such as EnterCriticalSection() or WaitForSingleObject().

  • The API matching algorithm cannot be totally comprehensive, and therefore some APIs that could be mapped to other categories may also appear as synchronization because a frame in the call stack eventually reached an underlying kernel blocking primitive that was mapped to this category.

To understand the underlying cause for a thread blocking event, carefully examine the blocking call stacks and profile reports.