Profiling with Xperf

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
About brucedawson I’m a programmer, working for Google, focusing on optimization and reliability. You should see a entry for this that you can select if VS is installed. Star 3. Some tools, such as powercfg, also use the kernel ETW providers and therefore cannot run at the same time that wprui is recording. June 18, at am.
 
 

Windows 7 ISO File Safe Download: All Editions (32 & 64 Bit).GitHub – microsoft/perfview: PerfView is a CPU and memory performance-analysis tool

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After that, enter the BIOS and set the installation media as the boot option. Then follow the on-screen instructions to install Windows 7 on your computer. This operation helps you perform a Windows 7 clean install. Having writing articles about computer tech for a long time, I am rather experienced especially on the aspect of computer optimization, PC enhancement, as well as tech terms explanation.

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Xperf Basics: Recording a Trace (the easy way) | Random ASCII – tech blog of Bruce Dawson – In This Section

Traces can be captured fine without this option for example, from nightlies , but the stack information will not be useful. Microsoft’s documentation for xperf is pretty good; there is a lot of depth to this tool, and you should look there for more details. It might already be installed by the Windows SDK. There seems to be a bug in xperf and symbols; it is very sensitive to when the symbol path is edited. If you change it within the program, you’ll have to close all summary tables and reopen them for it to pick up the new symbol path data.

Jun 1, Jun 14, Apr 19, Mar 13, Set indentation for project files in. Nov 11, May 9, TraceCodeAddresses: avoid linear growth resizing, cache strings for real. Oct 30, Jan 3, Harmonize the license in the source and in the nuget packages. Nov 12, Isolate NuGet configuration from global machine-state. Mar 16, Default PerfView to bit and remove PerfView Mar 2, Upgrading to.

NET framework 4. Mar 3, Microsoft mandatory file. May 16, Test Pipeline. Use multi-proc build. Fix support for building PerfView in Visual Studio Feb 26, View code.

Are you here about the TraceEvent Library? In this article. What’s New in the Windows Performance Toolkit. Windows Performance Recorder. Provides complete documentation for WPR.

You are commenting using your WordPress. You are commenting using your Twitter account. You are commenting using your Facebook account. Notify me of new comments via email. Notify me of new posts via email.

This site uses Akismet to reduce spam. Learn how your comment data is processed. Forecast for randomascii: programming, tech topics, with a chance of unicycling. Skip to content. Home About. Step 2 — get the sample providers and configuration files Update: stop reading now and go to the UIforETW announcement. Step 6 — record a trace For initial experimentation you might want to run the MultiProvider sample from the. You can display all events by using the View Preset dropdown to change views, and you can display the data as a table to see event details more easily The next graph shows Window in Focus information, which is another useful way of orienting yourself in a trace — note that this graph will sometimes be blank due to bugs in this provider The next graph shows CPU Usage Precise data which is an extremely accurate measure of CPU consumption, derived from context switch records.

I configured the columns so that if you display the table associated with this graph you can do idle-time analysis The final graph shows CPU Usage Sampled data. I configured it to display call stacks that are grouped by Process and Thread ID. This can be used for CPU busy analysis.

Trace file names with the year before the date so that they sort sensibly Adding these features, and perhaps a few others, would get rid of the existing clunkiness which makes wprui slightly frustrating to use.

That configuration file contains some other settings. Summary Use wprui. Like this: Like Loading About brucedawson I’m a programmer, working for Google, focusing on optimization and reliability. Nothing’s more fun than making code run 10x as fast. Unless it’s eliminating large numbers of bugs.

I also unicycle. And play ice hockey. And sled hockey. And juggle. And worry about whether this blog should have been called randomutf This entry was posted in Performance , xperf and tagged ETW , wpa , wprui , xperf. Bookmark the permalink. April 20, at pm. Kyle Sabo says:. April 21, at am. April 23, at pm. The NewThreadStack for this 5. Microsoft is kind enough to publish symbols for much of VS, as well as for Windows and about fifty rows down we get to the interesting details:.

Farther down in the call stack we can see that ntoskrnl. SYS which calls mup. Ponder that for a bit. That is, it satisfies the condition that the thread was waiting on. That might be a lock, an event, a thread, a process, or something else. Timer expiration is implemented by having a interrupt fire, the interrupt service routine schedules a deferred procedure call DPC and that DPC executes in the context of an existing thread.

If we know what MUP. SYS is then that gives us another clue as to the root cause, but even without that we know that Visual Studio called CreateFileW and it took a long time to return. In our selected region their are context switch events for many threads in devenv.

In fact, if devenv. The reason we are looking at thread 10, is because according to the MsgCheckDelay event it is the UI thread and it went for 5. It kept me waiting, and that makes me angry. If we sort by duration then we can just keep expanding with right-arrow. It contains too much glorious information. Click on the image for deeper details:.

We can see here that a Create file event, from devenv. The hang is because Visual Studio tried to open a non-existent network file, and sometimes that causes a 5. Hence the hang. The remainder of the hang is from a few other context switches and CPU time that account for the rest of the 5.

That looks more like the output from Perforce, only with back slashes instead of the forward slashes that Perforce uses. At Valve where I was working when I hit this problem build results are stored in Perforce so we have pre-build steps to check these files out. The checkout commands print their results to the Visual Studio output window. Since this whole thing started with me pressing F8 this means that Visual Studio was trying desperately to treat this potential file name as a source-file name associated with an error or warning message.

That explains the CResultList::AttemptToNavigate entry on the hang call stack — everything makes more sense once you understand the problem.

Once the cause of the hang was understood I modified our pre-build step to pipe the output through sed. This avoids the hang, and also made it so that F8 would take the selection to interesting errors and warnings, instead of to these mundane progress messages. I also reported the bug to the Visual Studio team. Having a trace is very powerful for this because it meant that I could tell them definitively what the problem was, and I could share the trace in order to let them confirm my findings.

Just like minidump files are a powerful way to report crash bugs, xperf traces are a powerful way to report performance bugs. Therefore its presence on the New Thread Stack and the Ready Thread stack was a clue that a network delay was the problem.

Some wait analysis investigations are more complicated than this one. In several investigations I have found that the main thread of a game was idle for a few hundred milliseconds waiting on a semaphore, critical section, or other synchronization object. In that case the readying thread is critical because that is the thread that released the synchronization object. Once I find out who was holding up the main thread I can move the analysis to that thread and apply either busy-thread analysis CPU sampling or idle thread analysis finding what that thread was waiting on.

Usually just one or two levels of hunting is needed to find the culprit, but I did recently trace back across six context switches in four different processes in order to track down an OS scheduling problem.

When following wait chains it is important to understand the order of events. If thread is readied by thread at time For CPU activity this is dealt with by selecting the region of interest. For context switches this is dealt with by drilling down all the way and then looking at the SwitchInTime s column. This column records the time of the context switch. The OS synchronization primitives are instrumented with ETW events that allow, in almost all cases, perfect following of wait chains.

The ability to profile your code trumps any small performance improvement. Only by following the chain of readying threads and looking at other information can you be sure to find the cause of your idle stalls.

When you notice a problem you can just record the buffer to disk, and do some post-mortem profiling.

– Windows 7 xperf free

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Both of these methods rely on WPA to control when process heap tracing begins. This is the case for both new processes and existing processes. Advanced users and developers recognize a number of issues that would arise when using either of these methods. Ideally, the use of an intermediate software layer to arbitrarily control process start times should be avoided. The analyst should have complete control of process starts.

By giving the analyst this level of control more meaningful data can be collected. Also, as a side benefit of direct control, the number of processes that can be tracked is increased as are the dependencies between several interacting programs.

For example, WPA requires administrator privileges. As a result, all processes launched by WPA inherit administrator privileges.

In addition, some processes cannot be run with administrator privileges. Also, in some cases, particularity with services, WPA does not have the correct security context. The result is the service process will not execute. The better case is to begin tracing automatically when a process starts. By beginning tracing automatically when a process starts with IFEO, the process uses the regular security context of that process. Starting heap tracing at boot times is not possible using command line syntax.

This allows the analyst to develop a complete picture of process heap usage throughout the entire boot process and subsequent activity. The following two examples will demonstrate how to implement these techniques.

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