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Tracing VirtualAlloc With Xperf – MozillaWiki
When analyzing a new and unknown problem there is no replacement for loading the trace into WPA and following the clues to a solution. I recently hit some multi-minute delays on my workstation. After investigating I found that the problem was due to a lock being held for five minutes, and during that time the lock-holder was mostly just spinning in a nine-instruction loop.
I seem to have a habit of writing about super powerful machines whose many cores are laid low by misuse of locks. But this one seems particularly impressive. I work quickly on my computer and I get frustrated when I am forced to wait on an operation that should be fast. However, Xperfview is no longer supported. All recordings must be opened and analyzed by using WPA. NET Framework 4. WPR provides built-in profiles that you can use to select the events that are to be recorded.
Alternatively, you can author custom profiles in XML. For discussion of key scenarios, see WPR Scenarios. Enabling Stack Walking A really cool feature that Xperf provides is the ability to capture stack traces of various events that occur during the trace.
Stack walking is enabled by specifying the —stackwalk command and, much like the events in the previous examples, we must specify each individual event for which we want this option enabled. The list of stack walking options is too long to list here. The full list of stack walking options is available in the stack walk help:.
As an example, we can enable the profiling kernel event, and pair that with the profiling stack walk option:. This means that the best thing to do is trial and error, just bring up the provider list with —providers kf and the stack walk list with —help stackwalk and try to come up with combinations that make sense. From there, we can bring up a Summary Table of an interesting period in the trace and add the Stacks column. This gives an impressive view into the call trees of each module during the period, shown in Figure 9.
Right clicking any entry in the call tree brings up two options: Callers and Callees. These options allow us to open new summary window with that entry presented as the root. This allows us to narrow the focus down instead of trying to sift through lots of other uninteresting call frames.
As mentioned previously, Xperf is mostly focused on capturing kernel mode traces. This means that our previous start and stop commands can be abbreviated to:. As another shortcut, the merge step can be incorporated with the stop command via the —d switch:. As a final round of shortcuts, the —f parameter and the —stop parameter to the above commands are also optional.
Thus, you might see someone starting and stopping a kernel trace with the following:. In addition, instead of providing a list of events that we want to view from the provider, we simply choose all events of the provider by giving the user mode provider name as part of our —on switch.
Strange, but true. After then doing a sidebar related activity adding and removing the Clock gadget in my case , stop and merge the trace:. Firing up the resulting ETL file in XperfView results in a series of events displayed and the Summary Table view indicates the events that the sidebar provider fired during the test See Figure To start the recording, just select the Start button.
This will launch the system event recording process. The next step will display the path to your ETL file. The most convenient way to immediately move on to your performance analysis is to select the Open in WPA button. This is a special log file only certain apps can open. You can select any of these charts on the left to see them displayed in more detail in the right pane.
In each chart, like the CPU Usage chart, you can hover over any graph area to see a breakdown of the data components like process name, process active time, and percentage of overall CPU usage.
This can help identify whether operating system processes or application processes are eating up all CPU time. You can also drill down into each process to see specific stack activity, again with the graph above highlighting areas when that stack was actively using CPU time.
Again, you can select any of these sub-charts to display them on the right.
Xperf windows 10.Xperf Profiles
The issue was caused by the Microsoft Pro IntelliMouse. In Device Manager (View → Devices by connection), the mouse device tree shows up. Microsoft has revamped the tool and split it into the Windows Performance steps: To that end, this article will focus on gaining access to these tracing points via the Xperf utility and interpreting the resulting data with the XperfView.