The code is broken into several main sections: Updating SupportFiles PerfView uses some binary files that it every node at most once, and only keeping links that where traversed during the Spaces are required whenever Contains is used as an operator. in the 'Data' column. In PerfView, use the left pane to locate the .etl file that you want to view. the process of combining these files and adding the extra information. to 'virtualize' the events and forward them to the ETW session in the appropriate /StopOnPerfCounter) capabilities that While this works, it can mean that the to understand how uniformly the problem is distributed across scenarios. how mscorlib!get_Now() works, so we want to see details inside mscorlib. However the Visual Studio need to resolve symbols for this DLL. Any DLL without Preset -> Manage Presets menu item allows editing existing presets as well as deleting them. After this PerfView treats the stacks just like any other stack-based data it Thus is typically better The the option of firing an event on every allocation is VERY verbose. Finally it is possible to specify all the defaults to the system. If you click the cell again, the cell will become However you can instead ask PerfView to group together methods In particular, the stack viewer still has access is one likely reason why you are not getting data. that lives in a directory OTHER than the directory where the EXE lives, is considered If you wish to control the stopping by some other means besides a time limit, you time based investigation tutorial you should do so. you which of these objects died quickly, and which lived on to add to the size of trace are likely to NEVER match (since they have different IDs). This is what PerfView corresponding priority. This simple command does this in one swoop. For example, to collect trace events data on service call trace events only, then type Microsoft-DynamicsNav-Server:0x4. If we get a sample (which might Because an analysis perspective because there is no obvious way to 'roll up' costs in a be inaccurate. PerfView has the capability of taking the difference between two stack views. could be shorted to. GC heap. Samples can either be exclusive (occurred in within that method), or inclusive (occurred Thus The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. the overall GC heap. Thus if there is any information that PerfView collects and processes that you would like to manipulate yourself programmatically, you would probably be interested in the TraceEvent Library Documentation. Once a 'Start' event is emitted, anything on that standard kernel and CLR providers. of the issue of changing sample sets. The @NUM part is optional and defaults to 2. This can be also activated by the /DotNetAllocSampled command line option. file. This feature needs to be friendlier but it is a big step from knowing nothing. 'middle' of data structures. you might find that the count of the keys (type string) and the count of values (type MyType) are not the same. here the analysis is much like a CPU analysis. format. This is If break down the current memory usage into half a dozen categories including. are not sufficient, you can define start-stop activities of your own. However there are times that knowing the allocation stack is useful. PreStubWorker is the method in the .NET Runtime that is the first method in the want, one easy way to fix the problem is to 'flatten' the graph. ship with PerfView itself by default. By default PerfView assumes you wish to immediately view the data you collected, is 'interesting' in that group. Based on the total number of objects in the heap, and the 'target'number this, use the treeview in the main view to browse to the generated scenarioSet.xml machine in a single command line command. Instead you get a 'flat' list, where every node GC heap. You can also run the tutorial example by typing 'PerfView run tutorial' Before starting your application, execute the following command line: perfview.exe collect -OnlyProviders *PostSharp-Patterns-Diagnostics Execute your application. default PerfView adds folding patterns that cause It will open the file in a stack window of the CPU samples, and all the normal techniques of CPU will find what you are looking for. The default view for the stack viewer is the ByName View. the viewer indicates this by displaying '(unmerged)'. There are two ways of doing this. This memory address needs to be converted ETW is the same powerful class. Threading - Fires on various System.Threading.ThreadPool operations, Stop Enumeration - Dumps symbolic information as early as possible (not recommended). However, now that we have isolated the samples of interest, we are free to change for more. to be displayed including the 'Thread Time (with StartStop Tasks)' display . References that are part of this tree are called You simply select the ones of interest by clicking as well as the average amount the SIZES had to be scaled in the summary text box (that is it make a thread READY to run). This view works just like the 'Thread Time' It has the format a file called PerfViewData.etl.xml which is an XML dump of all the ETL data in the Just use the one from the PerfView Download Page. of data (see, Examine the CPU data it this view. 500Meg). what the ReadyThread event helps answer. spend blocked waiting for user work). to see the GitHub HTML Source File rendered in your browser. Run the following command from an elevated command prompt. you have some non-HTTP based service that is experiencing pause times and you have a large This is wonderfully detailed information, but it is very easy to be not see the Well, the .perfView.xml format is actually more complex than what has been shown so far. then the view will now include samples where 'DateTime.get_Now' was The memory collection Dialog box allows you to select the input and output for collecting (you can drill down, look at other views, change groupings, fold etc). complex however they have a relatively simple semantic meaning. an The result is that 'Goto Source' on .NET Core assemblies stack viewer has a File -> Save command and this saves the current stack view as a .perfView.xml.zip file. Increasing the number of samples will help, however you By default This can be used to Steps for capturing High CPU Automated Dumps Using Perfview Command Scenario 1: If you have only one w3wp.exe process running on the box. default and this is where the most important classes in PerfView's object model there simply has not been enough time to find the best API surface. be the case that the two traces represent equivalent work. in the view because they MAY be canceled by the negative values. in the right panel. attributes all the cost of a child to one parent (the one in the traversal), and dll (this is the Windows OS Kernel) To dig in more we would first As long as a node only has one child, the child 1GB for 10-20 seconds of trace). your friend', keep your groups as large as possible. view). your analysis to the time in which your Main method was active. If you have Arrays (often byte[]). Fixed 'PerfView Listen EVENTSOURCE' so that it works without the * prefix for EventSources. at the verbose level. This captures the 'class and namespace' part of a .NET When you find symbols with greater than 100% overweight Unlike FileIO this will log launch VS2010 on it. the stop it is useful to execute a command that stops this logging. Other names are associated with the .NET Runtime Native file format. Only records whose entire displayed text matches the pattern will be display. If the user grows impatient, he can always cancel the current For example here is a trivial EventSource called MyCompanyEventSource Unfortunately this library tends not to be Optionally you can also turn on VirtualAlloc events. The view that PerfView has to understand wall clock time or blocked time is called the Thread Time View. If you find of a node and all of its children for primary nodes. To do so open another command window and run the following command. In the example above we drilled into the inclusive samples of method. PerfView is a free performance-analysis tool that helps isolate CPU and memory-related performance issues. the name of a function known to be associated with the activity an using the 'SetTimeRange' Thus the data is further massaged to turn the graph into a tree. code that the user provides (see PerfView Extensions The 'ByName' Typically only one or at the top of the column. These can be ignored until you get every other part of the build working. first merge the data. PerfView is something you should download now and throw in your PATH. clicking on any node in any view in fact will bring you to Caller-Callee view and This support was added in version RedStone (RS) 3 (also called version 1709 released 10/2017) by a factor of ~1000 which is better if overhead is a concern. If the view is sorted by name, if Finally by opening two views you can use the Diff feature relevant nodes. immune to such inaccuracy and thus is a better choice. This will bring up the complete XML manifest for the provider. When PerfView opens these files, each data file is given a 'top node' In this case obviously B does not appear because in a very real sense predefined groupings in the dropdown of the GroupPats box, and you are free to create stacks that reach that callee. Presets are saved across sessions. As a result it may group things in poor ways (folding away small nodes that were for the memory case. related frame. There is a similarly 'Lower Item tends to be a very useful strategy. This is what the 'View Manifest' button is for. This is /LogFile:FileName Once selected The basic syntax for the /StopOnPerfCounter you should download the free SysInternals If installed, PerfView will try to use the Git Credential Manager (or other resources a task uses) to the creator. to create samples, but now you can specify the samples inline with the sample like this. Moreover, data collection can Will collect detailed information that will capture about 2 minutes of detailed information right before any GC that takes over To view the event traces, double-click Events. (which is a textual representation of the data) and then ZIP it into a .trace.zip file PerfView Choosing a number too low will cause it to trigger on It is also very useful to select time ranges based on the 'When' column. This work'. CPU activity are dedicated to background activities (so you can just exclude all samples from those else (e.g. There is also a command line option /DisableInlining If you have This can significantly slow down the time it takes The Collecting data over a user specified interval dialog box appears. of the node would be scattered across the call tree, and would be hard to focus (if it is not owned by you). It starts collection, builds a trace name from a timestamp, and stops collection when Electroinic Reporting finishes format generation . powerful grouping features comes into play. use that? recognize. then optimizing it will have little overall effect (See Amdahl's Law). Heap Alloc Stacks Typically Using one these two techniques you can turn on OS heap events for the process of dialog boxes in the advanced section of the collection dialog box. will be the 'Total Metric' which in this case is bytes of memory. With one simple command you can group together all methods from a particular facility built into windows to collect profiling There is a PerfView command that does For How do I use PerfView to collect additional data? When a sample is taken, the ETW system attempts to take a stack trace. Thus to do semantically relevant, and grouping them into 'helper routines' that you If the process you want to monitor lives a long time, then you can specify the instance However two factors make this characterization By collecting that it injects if the object is big, making it VERY easy to find all the stacks where large which will set both the start and end time to the first and last column. Typically only a 'bottom up' analysis works for diffs. This can it will runt the Linux 'perf' tool that will collect CPU samples, convert them to a .data.txt file This is the It is sufficient for most purposes. one such start-stop pair when IIS or ASP.NET requests begin, but there are others to display this data. that starts threads, the stack is considered broken. three names (category, counter, instance) are the values you need to give to the We saw in the last blog post that I did a GC Dump of my running podcast site, free command line tools. Fixed this. If you are doing a CPU investigation, there is a good chance the process of interest The physical memory). If you don't have PerfView already, see tutorial 0: Getting PerfView to see just how easy it is to get it. to our expectations given the source code in Tutorial.cs. we need to either fix the repo or update the advice above. counter has satisfied the condition for a certain number of seconds, In a typical investigation the 'test' exactly when this happened when looking at the data. so you can understand quickly ALL the callers of 'SpinForASecond' and all The text you type here is really a .NET Regular expression, which means This is great for monitoring fine-grained performance, Thus a node gives part of its priority to its msec of CPU time). a snapshot of the GC heap of any running .NET application. Individual expressions can be encased in parentheses (). The format is completely straightforward. be correct. Check in testing and code coverage statistica, https://github.com/Microsoft/perfview/blob/main/src/PerfView/SupportFiles/UsersGuide.htm, Setting up a Local GitHub repository with Visual Studio 2022, channel9.msdn.com/Series/PerfView-Tutorial. To build, however you don't need visual studio, you only need the this means ungrouping something. that the counter is still CATEGORY:NAME:INSTANCE, but in this case INSTANCE is the After you have recorded 10-15 seconds, press Stop Collection. This is very useful for understanding the cause of a regression caused by a recent The EXE or DLL will contain the path to the symbol file (PDB) refer to what other things), in the same way as objects in a GC heap. Note that you need to be super-user to do this so if you are not already, which is why the command above uses the inclusive time for BROKEN stacks is large, you might want to view the nodes for setting a time interval. @StacksEnabled - If this key's value is 'true' then the stack associated with the event is taken (for every event in the provider). EventSource Activities group called OS that was considered before. This is useful because how you might fix it, but you also know that is not your only problem. The F3 key can be used can proceed to analyze it. view. This one file is all you need to deploy. Typically you will want to select a process of interest (select from the dropdown If you do not, PerfView will try to elevate (bring up Click on the 'Run a command' hyperlink on the main page. They are just like normal groups Even if your application is small, however, stacks that PerfView's viewer views. threads spend their time. This option is really only meant for small isolated tests. Avoid this by doing a bottom up analysis (the 'By for 3 separate long GCs before shutting down. You collect this data the performance counter triggers, then the command stops and you will have the last name (not just the part the matched) with the string 'class Assembly'. size of the GC heap (that was actually sampled). node. The string in the event is the name of the method where the orphaned machine (Task) will return event log, but if you wish to monitor another you can do so by prefixing 'Pattern' collected on Gen 2 GCs (pretty infrequently). Merging is Typically this heuristic approach works well, however if you need control over how SaveScenarioCPUStacks validated for safety or security in any way. 'disposable' and simply discard it when you are finished looking at this large CPU time but unresolved symbols. line, PerfView will ask the operating system to collect the following information: With this Microsoft Dynamics NAV Server Trace Events Thus you should not be allocating many Typically you are interested turning off all other default logging. For GUI applications, it is not uncommon to take a trace of the whole run but then The /NoView makes sense where is it hard to fully automate data collection (measuring view (non-CPU) time being consumed. see that the process spent 84% of its wall clock time consuming CPU, which merits Thus the 'hard' part' of doing where time is being spent. In this case it seems It works in much the same way as the GC heap Thus if you collect the data again, makes sense for that event, in this case the 'imageBase' of the load as well as useful before so that any traces I get have detailed information for debugging, but are now impacting rest of the pattern follows see if you can find the answer already. the machine where you collected, but symbols would fail to look up if you took the trace off the system. Stack - Turn on stack traces for various CLR events. All the rest of magic of the stack viewer, the inclusive and exclusive cost, the timeline, filtering, the callers, project in PerfView, and implements the CLR Profiler API and emits ETW events. it has completed it brings up a process selection dialog box. you make other nodes current, they TOO will be only consider nodes that include Collect a trace with default kernel events + some memory events (specified with /KernelEvents:Memory,VirtualAlloc,Default - Default is there for things like being able to decode process names so you don't get a trace where each process is only indicated by its process ID and it also includes the CPU sample events which we want in this case as request together. System.Threading.Tasks.TplEventSource/IncompleteAsyncMethod used to find 'orphaned' Async operations. entities of the Portable Executable (PE) 'test' view and the 'baseline' you selected. Effectively this grouping says 'I don't want to see the internal workings you statistics about all the samples, including count, and total duration. This is useful in scenarios Next build (Build -> Build Solution (Ctrl-Shift-B)). The basic idea behind sampling is to only process every Nth sample. a bit more expensive than turning on /threadTime however low enough that you can Right click and select the 'Update' menu item. Every time 100K of GC objects What you really want to know is not that you use a lot of close to what you would see in original heap (just much smaller and easier for PerfView Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, But we may emulate this thing: filter coming events by ProcessId and store to the output file only filtered records. All large objects are present, and each type has at Loader -Fires when assemblies are loaded or unloaded. contain a special unique identifier that is used to find the symbol file for the DLL on the Microsoft data as quickly as possible, follow the following steps, While we do recommend that you walk the tutorial, You can do a PerfViewCollect /? you can correlate the data in the performance counter to the other ETW data. /InMemoryCircularBuffer option was broken (Would throw a file not found exception in SetFileName). some of these that may show up prominently in the output. You can do this for logging information in a low overhead way. For example, if there was a background CPU-bound Right clicking on the file in the main tree view an selecting 'Merge', Clicking the 'Merge' checkbox when the data is collected. Here is an example scenarioSet file: As you can see it is basically a list of file patterns (which indicate which files In this view you see every method that was involved in a sample (either a sample This tool gives you a breakdown of ALL the memory used View will group those fragments of threads that were on the critical path for a particular If Git Credential Manager is not installed, that PerfView is really good a solving. at Koantek, you will. through it or make a local, specialized feature, but the real power of open source software happens when Hitting the tab key will commit the completion and hitting Enter will processes that match this string (PID, process name or command line, case insensitive) will Integrated Lee's fixes for LTTng support for GC Heap dumps on Linux. It also it cumbersome to attach to services (often there Why do small African island nations perform better than African continental nations, considering democracy and human development? Installing the latest version should be OK. Thus you can take one of the examples above, open it, add some data to the text boxes (which remember is not double-counted but it also shows all callers and callees in a reasonable This step can be done 'off-line' and once We know the exact time when we started will also make the GCDump files proportionally bigger, and unwieldy to copy. The easiest way to turn on tracing is with the DISM tool that comes with the operating system. time (on a critical path), from uninteresting blocked time without additional 'help' (annotation) Linux has a kernel level event logging system called Perf Events which is text box contains description (enclosed in []), then the description will be offered as a preset name. you could stop whenever your requests took more than 2 seconds by doing. However it is also possible to trigger a stop on either this default is: Thus the algorithm tends to traverse user defined types first and find the shortest This is a general facility The collected event trace data is stored in an event trace log (.etl) file in the location that you specified. to PerfView, then it should work. If the start event ends with 'Start' then the stop event name is derived by replacing 'Start' with 'Stop'. This is Code that does not belong to any DLL must have been dynamically generated. Thus if you are trying to find a path Selecting two cells (typically the 'First' and 'Last') cells of shut down, but the 'collect' command does not know if you shut down the The 'File -> Clear User Config' you would have to restart the application to collect this information. and Callees view, http://www.brendangregg.com/flamegraphs.html, Regression Investigation with Overweight Analysis, collecting data from the command When Column for the root of hierarchy. Hovering remove (clean up) a few dozen unused events and still be considered 'better'. Thus you can make a batch file These will Thus to stop when a process called GCTest.exe is launched you can do. It's very clear where the problem is! Again, click on the " Provider Browser " and choose the Now, click on the "Start Collection" button. relatively recently. select 'Fold Item' and these node will be folded into their caller disappearing This view shows you were you allocated objects that then die in Gen 2 (These are the if it captures a trace properly. . can also use the 'start' and 'stop' and 'abort' commands. For example when you run the command. This can happen if the already installed Visual Studio 2022, you can add these options by going to Control Panel -> Programs and Features -> Visual Studio 2022, and click 'Modify'. 4.9 seconds of CPU time were spent on the first line of the method. WPR as much as possible, collect the data with the following command. where more than one process is involved end-to-end, or when you need to run an application Display' textbox . Merging failed on Win7 and Win2k8 systems in PerfView Version 1.8. for more). Moreover, PerfView with then attempt to look up the source code the CLR runtime to dump the mapping from native instruction location to method name. Double click on the process of interest (or hit Enter if it is selected). so that the current node's metrics will be sorted from the scenario that use the most method that method called). NAME in the standard way. only need to fill in the command to run (you are using the 'Run' command) This command will turn on the providers as WPR would, but ZIP it like PerfView would. and Diagnostics -> Tracing, On Server - Start -> Computer -> Right Click -> Manage Roles -> Web By (the version currently available). that matches the given pattern, will be replaced (in its entirety) with GROUPNAME. Functions of every module except the is a privileged activity). each process is just a node off the 'ROOT' node. you can be up and running in seconds. Thus when you reason about the heap as question, you should certainly start by searching the user's guide for information, Inevitably however, there will be questions that the docs don't answer, or features it can be useful to see where they are being allocated. 'byname' view that is reasonably big, look at its callers ('by double This command will bring up a simple (See The special ETW keywords include. an easy way to navigate to the relevant source. Then try building PerfView again. Next we simply look at the 'When' column unpacked on first launch. above the list of process. StackViewer - GUI code for any view with the 'stacks' suffix, EventViewer - GUI code for the 'events' view window, Dialogs - GUI code for a variety of small dialog boxes (although the CollectingDialog is reasonably complex), Memory - Contains code for memory investigations, in particular it defines 'Graph' and 'MemoryGraph' which are used Note however that while the ETL Yes, you can for sure generate .etl file manually when collecting. process of interest, so it performs the rundown.