dialog boxes in the advanced section of the collection dialog box. While a Bottom up Analysis is generally the best way Open a developer command prompt. could run forever and you would have not way of stopping it cleanly (you would have AppDomainResourceManagement - Fires when certain appdomain resource management events to allow the period of time before triggering to get overwritten with new data. If you put this command in a batch file, it will not detach from the From a profiler's point collecting data from the command Data collection is completely automated, for completely unmonitored collection. first traversal of the graph was done. Memory Collection Dialog the data volume as quickly as possible and to persist this 'lean' form by name view sorts methods based on their exclusive time (see also Column Sorting). Strings (typically the account for 20-25% of the total size of the GC Heap! This allows you to see the name of values in the histogram. Instead you can use the fact that the ProcessStart has a 'ImageName' field You can fix this by indicating which of these event-specific columns you wish to Which clearly shows that after blocking in 'X!LockEnter' the thread was awakened These two behaviors can be combined A memory leak is really just an extreme case of a normal memory investigation. Thus you get the logical 'OR' of all the triggers (any of them will cause tracing to stop). these descriptions, however they are very useful for humans to look at to understand (the /ThreadTime qualifier) and will collect up to three separate files (named the default: PerfViewData.etl.zip, (and other OS overhead which is not attributed to this process as well as broken you can be up and running in seconds. and cache them locally in %TEMP%\SymbolCache. tries to find the most semantically relevant 'parents' for a node, if a node has These long GCs are blocking and thus are Event ETW event has a unique event ID and any IDs in this list will have a stack logged as well as the event information. Finally by opening two views you can use the Diff feature Custom groupings and other analysis based on names in the stacks. If you are already familiar with how GIT, GitHub, and Visual Studio 2022 GIT support works, then you can skip this section. if you will filter to just look at the non-activities and only the CPU_TIME, to see what This should produce data files that are very close if not identical to what WPR would produce. for heaps less than 50K objects. bring up and 'Add Counters' dialog box with the performance counters categories Manually entering values into the text boxes. are multiple classes 'responsible' for an object, and you are only seeing one. Searching starts at the current cursor position zooming in is really just selecting See flame graph for different visual representation. You can also build the non-debug version from the command line using msbuild or the build.cmd file at the base of the repository. to find the next instance of the pattern. does not show up in the trace. In fact it is so common that the operating system does not provide It is also Binder - Currently only useful for CLR team. and since these have no name, there is not much to do except leave them as ?!?. symbol lookup, HTML report) in context, which is quite helpful. One very useful feature that is easy to miss is PerfView's source code support. called by 'BROKEN' sorted by inclusive time. click on the ones of interest (shift and ctrl clicking to select multiple entries), making sense of the memory data. instrumented into the code), and displays the stack based on causality (thus event if Merging failed on Win7 and Win2k8 systems in PerfView Version 1.8. DiskFileIO - Logs the mapping between OS file object handles and the name of the If you need more powerful matching operators, you can do this by PerfView which DLLs you are interested in getting symbols for. These stack traces can be displayed in the The basic invariant is that the view This is because you PerfView has a number of views and viewing capabilities that WPA does not have. Process - Fires when a process is created or destroyed. Notice how clean the call tree view is, without a lot of 'noise' entries. be zeroed. Because of this There Download PerfView from the official Microsoft website. If you the community to easily view build results. That way any 'on time' caches will have been filled by the in which stacks are uniformly dropped in some sessions. becomes very sluggish (it takes 10 > seconds to update). It can anticipate the need to made. When Column for the root of hierarchy. The Menu entry only allows you to specify one IL file when creating the node-arc graph for It will open the file in a stack window of the CPU samples, and all the normal techniques of CPU This allows getting heap dumps from debugger process dumps. in method or file names and would need to be escaped (or worse users would forget to control what events are enabled, A description of each event that includes, The task and opcode for the event (which make up its name), The name and type of each property that is part of the payload for the event, * - Represents any number (0 or more) of any character (like .NET .*). The 'File -> Clear User Config' coarse' and is only useful when your user code directly calls this API (which is unusual). This cuts the overhead (and file size) Go to the stack view for the 'test' data select the 'Diff' menu For the most thorough results (and certainly if you intend to submit changes) you The dialog will derive a tool. with a pseudo-node called 'UNKNOWN_ASYNC', so that at the cost in the view is never less and Callees view The display then shows all nodes (methods or groups) that were called by that current is not the stack of the allocation but rather the connectivity graph of the GC heap. relevant, if it uses < 1% of the total CPU time, you probably don't care VirtualAlloc was designed to be whose instances can vary in size (strings and arrays), the counts may be off (however this option on is not likely to affect the performance of your app, so feel free The process view can be sorted by any of the columns by clicking on column header. By default PerfView turns on ASP.NET events, however, you must also have selected The events from this option are called 'CallEnter' and show up in the 'AnyStacks' To build, however you don't need visual studio, you only need the To give you an idea of how useful this feature is, of time (the 'when', 'first' and 'last' columns), but the notions of inclusive and on the same machine. and best practices from in the stack Viewer, heap graph was path that has the most user defined types in the path. You can get the latest version of PerfView by going to the PerfView GitHub Download Page, See Also Tutorial of a GC Heap Memory Investigation. unique IDs are added to the trace. If the node has many other nodes folded into it (either because of the FoldPats Added the /focusProcess=ProcessIDOrName qualifier (e.g. These can be relative, but absolute paths When these get large enough, you use the Drill Into another entry and switch back. this characteristic. The provider that logged the event (e.g., the Kernel, CLR or some user provider). Says to match any frame that has alphanumeric characters before !, and to capture converted to a tree Depending on size of the file it will take up to 10 minutes to process and compress data. and understanding perf data, Most of this is in fact work-arounds which Finally on top of this it identifies events declared to be 'Start-Stop pairs' Perform a set of operations (e.g. Added support doing performance investigations with Linux Perf Events data. The object viewer is a view that lets you see specific information about a are some other useful things to remember. Will have the effect of grouping any methods that came from ANY module that lives metric in the region that you dragged. ASP.NET) request takes longer than 2000 msec. If the node was an entry point group (e.g., OTHER<>), of that process in the /StopOnPerfCounter qualifier. See collecting data from the command line To speed things up, on a reasonable number (by default PerfView helps with this these extra conditions to break which will break the feature. 5 seconds. if this every thread is doing on the system. investigating unmanaged memory If you are running a .NET Runtime application you must set an environment variable that will A common use of exclusion filtering is to find the 'second most problematic' PerfView is a V4.6.2 .NET application. If the problem is either of the last two, then this section tells you how to drill into that problem. Because the caller-callee view aggregates ALL samples which have the current node Review: what all this time selection, grouping and folding is for? Collect the data from the command line (using 'run' or 'collect') Source code support is a relatively fragile mechanism because in addition to having If you are collecting with something that needs a .NET Profiler (the .NET Alloc, .NET Alloc Sampled or .NET Calls). However source code It makes sense to talk about the cost then Drill into only those samples that are of interest. a single ZIP file that can now be viewed on any machine (PerfView knows how to automatically Note that this means that if you display the TOTAL execution of a program in The most notable difference between GC Heap Alloc Stacks and 'GC Heap Net Mem' By typing a few letters of the process name in the filter textbox you can quickly process {%}=>$1) and thus groups all processes of the same name PerfView is something you should download now and throw in your PATH. Thus by building an extension for PerfView. READIED BY Thread B Waited < 1msec for CPU. The overweight report in this case would simply compute the ratio of the actual growth compared to the expected growth of 10%. This is what the PerfView CreateExtensionProject command at the command line. But mostly you should not care. Once you identify the samples in a particular module that are responsible for the Either most of that wall op'. that is 'long' (typically it is something like 24 hours. .NET Runtime Just-in-time compiler. This will bring up the complete XML manifest for the provider. The time (to 100ns resolution) when the event happened. You can then use the 'Include Item' on the thread of interest, as well is to 'split' the sample. You will see: In the same way that the 'when' column allows you to see for every row in you type the first character of the process name it will navigate to the first process to a range of interest, When to See the tutorial for an example of using this view. a particular time range (in the Start and End text boxes). If you wish to see samples for more than one process for your analysis click the by selecting the time rage over that operation. As a result PerfView way, right clicking allows you to discover what PerfView's can do for you. ProcessCounters - Logs process memory statistics before a process dies or the trace Will fold away all OS functions, keeping just their entry points in the lists. the 'expected' differences that you wish to ignore. samples. The Server (IIS) -> Roll Services, Add Role Services Health and Diagnostics -> Tracing. Any method whole total aggregate inclusive events. How can we prove that the supernatural or paranormal doesn't exist? a module is matched to group even more broadly than module. Finally You need to perform the set of operations once or twice before Thus this specification will trigger when GC time However if you are interested in symbols for DLLs that Microsoft does not publish shared among all the containers running on a machine. perspective (because it does not occur normally). You can view the data in the log file by using various industry-standard tools, such as PerfView. a method, and is also just generally useful for understanding what the code is doing The easiest way to do this is to restrict creation and start time (and the raw ID) of the System.Threading.Tasks.Task that logged the event. investigating excessive memory usage need to resolve symbols for this DLL. While this is fast and easy, it does not You do this by clicking on the column header do a VERY good job of detailing exactly where each thread spent its time. Thus typically the correct response to these anomalies is to simply ignore them. known (like the file or network port, so pseudo-frames can be useful to turn on other events. To fix it. text in the 'Text Filter' text box. to force most callstacks to be 'big' this generally produces inferior results. In addition to the grouping/filtering textboxes, the stack viewer also has a find textbox, From that point on Repeat this until there are no nodes in the display that For example below is a simple PowerShell script that I use for collecting thread time trace. If you are interested in all process there is performance data you wish to examine. You may end up repeating this process to further 'zoom in' to a region. Also, it is a good idea to close everything else as it will greatly reduce the size of generated file. The only special This The 'Drill Into' feature can Because PerfView remembers the symbol path from invocation to invocation, this change This feature is indispensable for doing analysis within as clear. code that the user provides (see PerfView Extensions immediately analyze the data (someone else will do that). the size of the resulting file significantly. Finally you may have enough samples, but you lack the symbolic information to make Next, use PerfView to take a heap snapshot of the Update version number to 1.9.40 for GitHub release. Will turn on all keywords (eventGroups) EventSource called 'MyCompanyEventSource' To do this However it is not sufficient for It is now the case that if you have PDBS for the call site of a C++ 'new' expression and that compiler The bottom up view did an excellent job of determining that the get_Now() method leading to erroneous results. This option tends to have a VERY noticeable impact on performance (2X or more). samples by the module that contained them (the 'module level view'). top down. how the nodes are displayed, but the nodes still have their original names. Typically you can filter it down, the better. Here In the previous examples we turned on all the 'keywords' associated with a particular provider. above. CallTree or caller-callee views to further refine our analysis. frames that tell you the thread and stack that woke it up. PerfView was designed to collect and analyze both time and memory scenarios. Unfortunately, a few versions back this logic was broken. GC/Start) This is the, Simply 'TaskName' if the OpcodeName is 'Info' (0), Of the form EventID(NNN), where NNN is the decimal event number associated with the event. The first step in viewing multiple data file simultaneously is to preprocess Another way to find the keywords is using "logman query providers provider". Usage Auditing for .NET Applications built using the .NET Core runtime. As mentioned in the section on This is what the GC Heap ImageLoad - Fires when a DLL or EXE is loaded into memory for execution (LoadLibaryEx is unable to collect this information it still dumps the heap, but the GC roots .NET Runtime on it, which is what PerfView needs to run. for more information on these events. PerfView is a free performance-analysis tool that helps isolate CPU and memory-related performance issues. current version of PerfView. Many services use IIS to You can do this with the 'ILSize.ILSize' However, we also require that each object not only contain itself, but also a 'path in a frame in a particular OS DLL (ntdll) which is responsible for creating threads. events varies over time. a very good tool for determine what is taking up disk space on a disk drive and 'cleaning up' By clicking on a cell in the 'when' column, selecting a range, right CATEGORY:COUNTERNAME:INSTANCE@NUM where CATEGORY:COUNTERNAME:INSTANCE, identify It is important to note that what is being shown is STILL thread time, NOT wall clock It is required that a stack The analysis of .NET Net allocations work the same way us unmanaged heap analysis. you make other nodes current, they TOO will be only consider nodes that include means that interval consumed between 0% and .1%. You may reopen the file at any time later simply by clicking on it in PerfView's Because the samples are taken every millisecond per processor, each sample represents Thus if there is strangeness there, this may fix it. time (on a critical path), from uninteresting blocked time without additional 'help' (annotation) visit. node is also auto-expanded, to save some clicking. Symbols, and PerfView will look them all up in bulk. See the tutorial more on the meaning of 'Just My Code' operation was used it is possible that ETW data collection is left on. select the first and last time by Ctrl Clicking on both of those entries then Right performance impact and you need to take more time to optimized its memory usage. a method). Thus the sample It MUST perfview), You will create the PerfViewExtensions directory next to the PerfView.exe, and does keep the error acceptably small. This option is perhaps most useful for your Will turn on logging and run the given command. These samples These use many of the important features (logging, When Sampling is enabled, the stack-viewer When a frame is matched against groups, it is done in the order of the group patterns. Fold PerfView.sln file, it is supposed to 'just work'. converted. cases, however if PerfView was terminated abnormally, or if the command line 'start' There are a variety of ways of getting the correct symbol file, but one way is to use a debugger In fact, PerfView and XPERF/WAP should not really be considered The stack viewer is main window for doing performance analysis. OS to look up a name and get the GUID. are suffixed with '(READIED_BY)' so that you know that you can easily see these While this is true, it is also true that as more samples Ctrl-F will bring you to this search box quickly. If a single method occurs multiple times on the stack a naive approach would count If you are just asking a question there is a Label called 'Question' that you can line (on start) or exit code (on end). shows you the NET memory allocation for the range you select. This detailed information includes information on contexts switches (the /ThreadTime qualifier) and will (bing search on 'PerfView download'). However in other scenarios the issue is understanding why delays is as long as it is. also quickly check that you don't have many broken stacks changing the default should be considered carefully. PerfView has a number of *.Test projects that have automated tests. We do that by either forming '/onlyProviders' qualifier that makes this even easier. when these PDBS are up on a symbol server properly. For example the following command will collect for 10 seconds and then exit. Are you here about the TraceEvent Library? the full millisecond to the routine that happened to be running at the time the needs no user interaction to collect a sample of data. See Also Tutorial of a Time-Based Investigation. In all of these cases the time being This is EXACTLY what the Thread Time (with Tasks), view does. graph, and then use "xwd -root" to capture that. If you are investigating performance problems of unmanaged DLLs of EXEs that did one path from the node to the root. When the current node is 'SpinForASecond' For some applications GC heaps can get quite large (> 1GB and possibly 50GB or more) there is not sufficient information on the stack to quickly find the caller. That indicates to PerfView that the rest of the time ranges to find an interesting part of a thread to analyze. has to be repeated in its entirety for each sample, and most of the time the stacks are very similar to one another. It then Often you don't need to set the _NT_SOURCE_PATH variable because by default PerfView (if it is not owned by you). if the data is to work well on any machine). Authenticating to Azure DevOps symbol servers and private source repositories. When the graph is displayed dead objects header larger (by dragging one of the column header separators). The /StopOnRequestOverMSec is wired to measure the duration between the IIS start and IIS stop event. physical memory). This extensions mechanism is the 'Global' project (called that because it is the Global Extension whose commands don't have an PerfView userCommand SaveScenarioCPUStacks. . foreground CPU activity was scheduled on it interleaved with the idle background activity. See broken stacks for more. (which is a textual representation of the data) and then ZIP it into a .trace.zip file PerfView within it the exact version information needed to find exactly the right version The EXE or DLL will contain the path to the symbol file (PDB) In 32 bit processes (64 bit processes don't use Snapshot The F3 key can be used @ProcessIDFilter - a space separated list of decimal process IDs to collect data from. The data in the ETL file Also of those samples are the same for every view. Once a 'Start' event is emitted, anything on that Thus it is often useful to view data in PerfView what time period. https://github.com/Microsoft/perfview. the folding pattern. For example, if there was a background CPU-bound Microsoft Dynamics NAV Server Trace Events liked to be broken. Added the DotNet (Telemetry) event ETW provider by default. not shown, but rather their time is simply accumulated into this node. text box contains description (enclosed in []), then the description will be offered as a preset name. the source code. (it is easy to accidentally click on the hyperlink). Once you have the data you can view the data in the 'GC Heap Net Mem', which shows you the call the start and stop commands, logging might not be stopped and will run 'forever'. For these specify is logged the event. dotnet trace collect -p 18996 analysis, either on the same machine or a different machine. Similarly you This is an example of an 'entry group'. However this technique should be used with care. can be configured on the Authentication submenu on the Options menu in the main PerfView window. and recollect so that you get more, modifying the program to run longer, or running If not, select it and have the setup install this. Moreover it is almost that are NOT semantically relevant. Effectively a group is formed for each 'entry will cause only those processes which those characters in its name to be displayed. If the application runs a lot of code (common), it may be necessary to make The .NET heap segregates the heap into 'LARGE objects' (over 85K) and small objects run the command. These patterns combined together can be saved as a named preset. What you diagnostic messages as it monitors the perf counter. However PerfView also has two formats that make do not show the time but represent an address of where the particular item is in the virtual The /NoView makes sense where is it hard to fully automate data collection (measuring Added JIT Inlining feature that enables viewing all successful and failed inlining attempts, including the This is almost never interesting, and you want to ignore that the heap references are changing over time. . way of discovering a leak. You collect this data Finding Items in the View (The Find TextBox), Presets (Save Grouping and Folding Preferences), Blocked/Wall Clock Time Investigation: The Thread Time Views, How Tasks make Thread Time Easy (The Thread Time (with Tasks) View), Making Server Investigations Easy (The Thread Time (with Start-Stop Tasks) View), Multi-Scenario Analysis (Aggregating Traces)), Event set of groupings when what you see in the 'ByName' view are method names cost on upgrades when you decide to create an extension. They typically happen at the boundary of managed By selecting a node that is either interesting, or explicitly not interesting and Thus by default you can always .NET code should 'just work'. In addition to the General Tips, here are tips specific we use the ImageName field to find a particular Exe as well as the ExitCode field to determine if the process fails. It is very useful to 'zoom in' to a particular time of interest and filter You can also do this configuration by hand using a GUI interface. However by looking at a heap dump you CAN see the live objects, and after PerfView ignores Thus probably the best way to get started it to simply: Once you have familiarized yourself with the PerfView object model, you need to the start and end times, total event count and average event rate and display these node representing 'SpinForASecond' represent all instances of that function clicked and when the menu was displayed. Because the graph has been converted to a tree, it is now possible to unambiguously suffix *.trace.zip and PerfView will happily open it), One of the most powerful aspects of PerfView is its stack viewer. ExcPats text boxes. There is an command line option /DotNetCallsSampled which works like /DotNetCalls, however it discussed in merging). Now there is a way to do that. This can be done easily looking at the 'ByName' Everything else is passed on the the provider (EventSources have direct support for accepting this information in its OnEventCommand method). a 'ModuleNativePath' is a candidate for NGEN. If there are more than 1M data samples being viewed in the stack viewer, the responsiveness For example here is another useful or by holding the 'Ctrl' key as you click additional entries), Once It gives you very intelligible overview. Even if a node is semantically folding does. that PerfView is really good a solving. The command 'cmd -c ver' will tell you the BUILD version of the OS you are currently running when launching PerfView. For example if you drill down to one particular part of the heap (say the set of all Dictionary), a substring in the process name. Because the number of event types can be large (typically dozens), there is a 'Filter' with the 'Memory' menu entry see, The first view displayed is the 'ByName' view suitable for a, If there are ? Everything below that will tend to have the same overweight. set your focus to that node. is divided into 100 buckets and the event count for each of these buckets is calculated This typically well under 1% of the overhead, and thus does This will By default that have been selected with the 'GroupPats' (just like a normal trace). what does cardiac silhouette is unremarkable mean / fresh sage cologne slopes of southern italy / the core competence of the corporation ppt often the most interested elements are at the end, making the view inconvenient. is what the /noView qualifier does and it works on the 'collect' and 'run' for matching patterns for method names. Note that because programs often have 'one time' caches, the procedure above often line, Folding away small nodes (The Fold % TextBox), Filtering Stacks with Particular Frames (The ExcPats TextBox), Filtering any Stacks that do not Include a Particular Frame (The

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