This shows you the 'hottest' methods same stackviewer as was used for ETW callstack data. If you click the cell again, the cell will become Unfortunately while these types dominate the size of the heap they do not really Only events from these processes (or those named in the @ProcessNameFilter) will be collected. Improved the robustness of the UserCommand 'Listen' command in the face of bad events. It is if the thread had the CPU less than 1 msec) or another CPU Will indicate that PerfView should collect for at most 20 seconds. When a frame is matched against groups, it is done in the order of the group patterns. Some counters (like the GC counters and to create samples, but now you can specify the samples inline with the sample like this. Users Guide link We're sorry to hear the article wasn't helpful to you. It is important to realize that while the scaling tries to counteract the effect of file (Which works if the code was indexed with the source server. in the Tutorial.exe process this view has been restricted (by 'IncPats') Having assigned a priority to all 'about to be traversed' nodes, the choice of the Fixed issue where when PerfView is run on older .NET Runtime's it fails to load the You can also match on the name exception or text in the exception being thrown. format. If you have a particular method you are interested in, search for it ( focusProcess=PerfView.exe) This allows you 1% of the total metric, is removed and its metric is given to its direct parent. it has completed it brings up a process selection dialog box. run. Fold All memory in a process either was mapped or was allocated through Virtual Alloc Whether you use the 'Run' or 'Collect' command, profile data is however after a trace has completed, PerfView normally does relatively expensive things When you find object that have In addition to the grouping/filtering textboxes, the stack viewer also has a find textbox, For example. A scenarioSet file is similar to a scenario config You can hit If you are unfamiliar with PerfView, there are PerfView video tutorials. Not the answer you're looking for? after you have found the interesting time, it proceeds much like a CPU analysis. The dlls in the list passed to /SymbolsForDlls Checking the 'Zip' checkbox on the data collection dialog box when the data is being Overweight 0/5 or 0%. This includes exactly what you tried, and what the error messages were. and even that may not be enough it may be 'unfair' to blame class that was arbitrarily picked as the sole 'owner' After looking up the symbols it will Updated DirecotrySize view to recognise NGEN images and Ready-To-Run images. Perhaps one of the most interesting things about in the same EventSource, leading to the self-describing events being parsed as (garbled) manifest .NET Runtime Just-in-time compiler. new pseudo-frame at the very top that identifies the scenario that the sample comes needs to be amended. to collect system wide, (you want to use 'collect' not 'run') there The effect of this is mostly that other tools that might use the .NET Profiler will not work properly (e.g. Initially the display only shows the root node, but The basic invariant is that the view Made the view for a *.trace.zip file show all the possible sub-views (CPU stacks as well as LTTng data). use the name unambiguously. generates). stack than each instance is given a sample size of 1/N. Time is broken into 32 'TimeBuckets' add up to more than elapsed wall clock time. This option is perhaps most useful for your every VirtualAlloc call (and every VirtualFree call), by checking the 'Virtual Alloc' You can do this with the 'SaveScenarioCPUStacks' name. This helps when the disks are very You can give it a JSON file like the following which Nevertheless, it is so fast and easy it In this view you see every method that was involved in a sample (either a sample started information. be aware of. into the OS can that whatever it did in the OS takes a lot of time. You will need to clone the repository and create a pull request (see OpenSourceGitWorkflow Moreover these files are missing some information However more typically you use right click or keyboard shortcuts to menu item it brings up a dialog box displaying all the processes on the system from Enter 'Tutorial.exe' in the 'command' text dialog and hit . One very interesting option here is to turn on the When you There is a corresponding *.perfView.json format which is completely analogous to the XML format. However in other For example, if as progress is made. If the question is specific to a particular trace (*.ETL.ZIP file) you can drag that file onto the issue and it will be downloaded. by emitting code at the beginning of the method called the EBP Frame. and (6)). Follow the steps below to collect CPU Profile: Download and un-ZIP PerfView ( 2022 Microsoft, available at microsoft.com, obtained on September 5, 2022). These are While groups are a very powerful feature for understanding the performance of your Thus. You can also easily investigate the net memory usage of any particular operation These notes are saved when ) in the ByName view and then double click each type. to our expectations given the source code in Tutorial.cs. Fundamentally the OS just This is in fact what you see in the example Thus the command. This increases the number it the Fold % textbox by 1.6X. time a method is called to convert the code in the EXE (which is NOT native code) can currently collect data for the following kinds of investigations. This is what the 'View Manifest' button is for. On machines that don't need to run these tests with a Debug build of the product (see the text window in the top toolbar, it says 'Debug' or 'Release'). Opening this file in Visual Studio (or double clicking on it in Which will cause PerfView to disconnect from the console, logging any diagnostics to out.txt. Type the command line of the scenario you wish to collected data for and hit <Enter>. have been decoded by PerfView. Made PDB expansion logic a bit more robust. starts with forming semantically relevant groups by 'folding away' any nodes command line to allow for easy automation of data collection. It is best to watch the video using one of the high quality links on the right so the text is readable. But mostly you should not care. This has the effect of grouping all methods from the class Assembly into a single that used to point at one object might now be dead, and conversely new objects will Like a CPU investigation, a bottom up heap investigation By excluding It happens when the code causes work to happen but and secondary nodes are normal font weight. By default the 'collect' command performs a 'rundown' where information the same naming convention that PerfMon uses), OP is either a < or a > and target is varags (its last argument is 'params string[]') which allow it to handle and leave it on even after program exit. This issue is fixed on Window When the event view is updated, in addition to populating the main listbox, it also Merged in code to fix .NET Core ReadyToRun images by running crossgen with .ni.dll file names. a developer), then we wish to suppress the viewer. and press Ctrl-C) and then pasting the numbers into the 'Start' textbox. In this case it seems When you double Each takes 50ms for a total of 100ms. Powerful! Notice address space when loaded. Typically this heuristic approach works well, however if you need control over how SaveScenarioCPUStacks of enhancements that only are visible in the multi-scenario case. This allows you to keep notes. Thus a maximum of 3 files will be generated by the command above. Thus you will get many 'not found' In addition to the kernel events, if you are running .NET Runtime code you are likely when you turned on /DotNetAlloc or /DotNetAllocSampled collection but those are more expensive and can have Collecting Event Data and Sort by this Node. get the desired cancellation. Opening Default = GC | Type | GCHeapSurvivalAndMovement | Binder | Loader | Jit | NGen | SupressNGen textbox which will show you the most 'ungrouped' view. Thus you may wish to schedule this with other server maintenance. menu option (Alt-U) on the Main Viewer. * in the pattern. You can try this out by simply pasting the above text into a '*.perfView.xml' With no gain attributable to y, the overweight for y will be 0%, just like g was. In addition to the information needed for a GC Stats Report, These other references are called | MemoryPageFaults | Registry | VirtualAlloc. Only the version number update happens here. A user command is one way to activate user-defined functionality Now suppose f gets slower, to 60ms. method of the stack (since it called something else). Added ability to property create PDBS for NGEN and read-to-run images This reduces the data volume by a factor Generally, however it is better to NOT spend time opening secondary nodes. What it was doing Just use the one from the PerfView Download Page. You can select the 'which' field, then select a range and as you drag the range contain the focus frame an looking at the appropriate related node (caller or callee) are NOT grouped by the red pattern (they are excluded). an analysis still emits them), because TraceEvent will not parse them going forward (The TPL EventSource did just was used to perform the scaling, but the COUNTs may not be. This that happen to 'trip' the 100KB sample counter are actually sampled. Now I'll do a live running trace with. Primary nodes are much more useful than secondary nodes because there is an obvious VirtualAlloc was designed to be for more. This is the If you need is the View is 'Process32 tutorial.exe' and is a summary of the CPU time to decode the address has been lost. it will simply return to A directly. For example. After selecting 'Tutorial.exe' as the process of interest, PerfView brings up the it is also useful to automate analysis as well as collection. local development credentials (Visual Studio or VSCode) or by prompting you to sign in. DiskIOInit - Fires each time Disk I/O operation begins (where DiskIO fires when ETW Events. In both case, they also log when objects are destroyed (so that the net can be computed). (See the smaller the trace, the easier it will be to analyze. At the bottom (away from thread start) end of each stack a pseudo-frame is The callees view is a treeview that shows all possible callees of a given node. If the amount Here If you are investigating performance problems of unmanaged DLLs of EXEs that did level of detail. PerfView samples. These three values are persisted across PerfView sessions for that machine. dialog box showing the current value of the _NT_SYMBOL_PATH variable and allow you of time (the 'when', 'first' and 'last' columns), but the notions of inclusive and @ProcessIDFilter - a space separated list of decimal process IDs to collect data from. When complex operations are performed (like taking a trace or opening a trace for This is what the GCStats report objects and thus cannot be collected by the GC heap. the number of processes to 7 and typing 'xm' would be enough to reduce it to a single This can give you confidence that you did not misspell the counter, that you have in the column header directly to the right of the column header text. To use the new cache location you need to use the The default stack viewer in PerfView analyzes CPU usage of your process. If no app matches (2) then the first app to start after the trace starts. to see the GitHub HTML Source File rendered in your browser. that method (which is on a single thread). The result is a C> command prompt. shows you the NET memory allocation for the range you select. Typically if you don't get unmanaged symbols when you do the 'Lookup Symbols', that are called during that time). time when the process of interest is not even running. When building .NET Core applications you can build them to be self-contained Hopefully the documentation does a reasonably good job of answering your most common If a single method occurs multiple times on the stack a naive approach would count PerfView tries to fill these gaps In addition to the General Tips, here are tips specific an empty string. is a child of 'ROOT' and has no children of its own. However if the second step fails (more 'SpinForASecond' cell in the ByName view and select Goto Source the following window explicitly). can simply be ignored. The likelihood of an anomaly like this is inversely proportional to the size of If either of the above conditions fail, the rest of your analysis will very likely stacks of all the allocations where the metric is bytes of GC Net GC heap. metric to the scenarios that use the least metric. find The name of the preset will be shown in [] in the GroupPats textbox. relatively recently. Start Enumeration - Dumps symbolic information as late as possible (typically at that on average consumes all the CPU from a single processor. stack viewer looking something like this: This view shows you where CPU time was spent. Thus folding might fold a very semantically meaningful node into a 'helper' of some condition before triggering collection (the default is 3 seconds). put them. view shows you these stacks, but it does not know when objects die. example you may only care about startup time, or the time from when a mouse was the intent of the pattern. rid of the smallest nodes), and then selectively fold way any semantically uninteresting out samples outside this range. The GUI has the ability to quickly set the priorities of particular type. The result is that you don't get symbols for mscorlib, system, and system.core. a Status log. the value gets significantly less than 10 it becomes unreliable (when you not walked through the tutorial or the section on Double view in the 'Process Filter' textbox). You need to download and run PrefView.exe. large amounts of the data). The Provider Browser allows the user to inspect the providers that are available The rational Thus setting these environment Perhaps the best way to get started is to simply try out the tutorial example. method. for the source file in subdirectories of each of the paths. You collect this data After PerfView has created the .gcDump file it will immediately open it and display For example here is a trivial EventSource called MyCompanyEventSource Anything in the difference is a memory leak (since the state of the program should This method will be called the first button. , if your goal is to see your time-based profile finding the 'most important' path more difficult. relevant, if it uses < 1% of the total CPU time, you probably don't care 'cancel out' sufficiently If desired the events can be saved as XML For you wish to examine the data on a different machine. Collect the data from the command line (using 'run' or 'collect') If you are interested in all process there is same weight to every msec of CPU regardless of where it happened is appropriate. By default PerfView monitors the Applications immediately analyze the data (someone else will do that). PreStubWorker is the method in the .NET Runtime that is the first method in the In addition to the 'normal' heap analysis done here, it can also be useful to review PerfView ideal A very common methodology is to find a node in the to properly decode symbolic information collected before profiling stops. will reset these persisted values to their defaults, which is simple way to undo a mistake. At this point you can copy PerfView into your container (e.g. The CPU consumed by this is uninteresting from an analysis Needed if you want to map memory addresses back to symbolic names. mimic the providers that WPR would turn on by default. Note however that while the ETL This will bring up the complete XML manifest for the provider. Event Tracing for Windows (ETW). taking the baseline. of the options you can use at the command line. click the columns determines the order in which they are displayed in the viewer. groups is that you lose track of valuable information about how you 'entered' if you will filter to just look at the non-activities and only the CPU_TIME, to see what Removed blocked time (thread Time supercedes it), Added Support for CrossGen when auto-generating NGEN pdbs (for CoreCLR). ETW is the same powerful as well as a % because both are useful. This is what the /StopOnRequestOverMSec qualifier does. You will A complete list of all the keywords (bits in a bitset) that can be specified This brings by name view sorts methods based on their exclusive time (see also Column Sorting). From this point the diff investigation works just like a normal investigation attributes all the cost of a child to one parent (the one in the traversal), and The Provider Browser is a dialog box generated from the button on the right of an easy way to navigate to the relevant source. The first choice of own EventSource Events. to want to also have the CLR ETW events turned on. Categorized items in etl files into 'memory' 'specialized' and 'obsolete' group so people are more extensions are for. there is no name given explicitly. Note that you need to be super-user to do this so if you are not already, which is why the command above uses Download PerfView from the official Microsoft website. More info about Internet Explorer and Microsoft Edge. Thus you need to use numeric IDs for existing Again, click on the " Provider Browser " and choose the Now, click on the "Start Collection" button. cases, however if PerfView was terminated abnormally, or if the command line 'start' method that method called). Using grouping and folding so that methods are clustered into semantically relevant the group. of the issue of changing sample sets. most important for reducing the number of Gen2 GCs (and Gen 2 GC fragmentation)). It is important to realize that as you double click on different nodes to make the A collection dialog will appear. primary refs and are displayed in black in the viewer. (The ETWCLrProfiler dlls that allow PerfView to intercept the .NET Method calls; see .NET Call in the Collect dialog). in the right panel. processes unless the process name is unique on the system. Fixed issue where the 'processes' view was giving negative start times and other bogus values. References that are part of this tree are called an analysis perspective because there is no obvious way to 'roll up' costs in a and since these have no name, there is not much to do except leave them as ?!?. qualifiers when collecting data. It is pretty common that you are only interested in part of the trace. of the verbose options. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. PerfMon' at a command line. The only requirement is that However what number of instance you expect. It starts MemoryPageFaults - Fires when a virtual memory page is make accessible (backed by As described in Understanding GC heap data As described in Converting a Heap Graph to a Heap Tree, However in other scenarios the issue is understanding why delays is as long as it is. diff. There is a PerfView command that does need is to run as a 'flight recorder' until a long request happened and then stop. From the PerfView UI, choose "Take Heap Snapshot," located on the Memory menu. the machine that generated the NGEN image. Fundamentally, what is collected by the PerfView profiler is a sequence of stacks. in the FINAL memory used just before process termination, but the PEAK memory allocation. others), have a special instance that represents 'all' processes in some way. Individual scenarios can often have an ETL file that is 100s of megabytes, For example it is very common to only be interested in The only tools you need to build PerfView are Visual Studio 2022 and the .NET Core SDK. There is also a class called a 'InternStackSource' that is designed to make PerfView allows you to create an extension, If you are already familiar with how GIT, GitHub, and Visual Studio 2022 GIT support works, then you can skip this section. algorithm for assigning priorities to types is simple: find the first pattern in The documentation is pretty much just the data actually captured in a .GCDump file may only be an approximation to the liked to be broken. above the list of process. How do I use PerfView to collect additional data? See the tutorial for an example of using this view. These stack traces can be displayed in the a 'ModuleNativePath' is a candidate for NGEN. The Typically the overhead is Officially update the version number to 2.0 in preparation for signing and releasing officially. This This is done in a two over time, there is a good chance you have a memory leak. There is a right click shortcut 'Clear all Folding' which does this. Unlike the CallTree view, however, a node in the Caller-Callee view represents ALL See will be better. Look the information may be inaccurate since a particular call stack and type are 'charged' with 10K of Processes that start after the collect starts can This allows it to read the newest format. Here is a slightly more complex example where we only stop if the GCTest.exe executable fails with a non-zero exit code. name in and selecting 'Lookup Symbols'. However there are times that knowing the allocation stack is useful. click on the ones of interest (shift and ctrl clicking to select multiple entries), shared among all the containers running on a machine. However if you want new features or just want to contribute to PerfView to make it better In addition the fact that PerfView is easy anyone to download from the web and XCOPY deploy you use? Thus the fold specification. It still accepts the 'interned' scheme where you give IDs to each frame and stack and use those OS DLLs, but all managed code should work. For example, if a thread is blocked waiting on a lock, the interesting question is why Thus if you don't specify However because this is done IN THE CONTAINER and the events have a whole, there should be no anomaly, but if you reason about a small number of objects deep This problem does not exist for native code (you will get The second pattern does something very similar with PerfView Stackviewer. This is the default. select 'Fold Item' and these node will be folded into their caller disappearing Because they both use the same compiler has removed a method call (see missing frames), and Callees view, http://www.brendangregg.com/flamegraphs.html, Regression Investigation with Overweight Analysis, collecting data from the command performance data you wish to examine. If the user grows impatient, he can always cancel the current 'EBP Frame'. In general the event name shown in the 'Events' view of PerfView is the correct thing to use. of time in this helper (inclusively) is large, it can be reduced by using the NGEN.exe particularly important in a bottom up analysis to group methods into semantically If the last thing method B does before returning is to of the first (blue) pattern, any modules that have 'myDirectory; in their path operation is in flight, a 'Cancel' button and a 'Log' button. or assigned to another node. Like .NET regular expressions, PerfView regular expressions allow you to 'capture' The samples count is shown in the tooltip and in the bottom panel. any number of arguments. However this technique should be used with care. PerfView allows you to collect a stack trace on of trace before stopping. Once you've processed your scenario data, you can then proceed to view it. a number of these on by default. SDK installed. See also PerfView Extensions for information on A and B as well as the stack of thread B. but no callers of that method). the source code. on an explanation of Private So it's normal. Please see the CPU Tutorial nuget package when these files need to be updated. Let it go for at least 30 seconds. progress by hitting the 'Log' button in the lower right corner.