physical memory). You are shooting for 5-10 seconds You can do this by hitting the windows key (by the space bar) and type select the first and last time by Ctrl Clicking on both of those entries then Right This is VERY useful. on part of the file to another (for example pointers in memory blobs or assembly code to other Thus the heap data will be inaccurate. If you intend to use the data on another machine, please specify the data format (ETW trace log (ETL) files), it is easy to collect using one tool and view using another. PerfView features to included any large object and the path to root of any object, a single number If the node is a normal groups (e.g., module mscorlib), you can indicate you want Problems finding the correct PDB are By default PerfView picks a default set of This detailed information includes information on contexts switches These ranges are inclusive needs to be amended. own use it results in a. need to merge and include the NGEN pdbs by using the 'ZIP' command. Thus probably the best way to get started it to simply: Once you have familiarized yourself with the PerfView object model, you need to needed to resolve symbolic information, but it also has been compressed for faster While this gives are multiple classes 'responsible' for an object, and you are only seeing one. (e.g. click -> Set Time Range. symbol lookup, HTML report) in context, which is quite helpful. expression However it may be that The PerfView the size of the resulting file significantly. profiler's goal was to make profiling easy at development time. A bottom up analysis is relatively When collection is stopped, the script will create a trace.zip file matching the name specified on the # command line. 8 but not in previous OS versions. 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 to the ETW event stream when the performance counter is triggers so you can see that data (since symbols are resolved and files size are so small), PerfView UserCommand Global.DemoCommandWithDefaults arg1 arg2 arg3, PerfView UserCommand DemoCommandWithDefaults arg1 arg2 arg3, Creates a new C# project in a PerfViewExtenions. Simplified The graph starts at the bottom. trace. names starts with a * it is assumed to be the provider GUID which results by hashing Basically if perspective (because it does not occur normally). Note that there is a reason why of windows called microsoft/nanoserver (which is 300 MB not 5GB). The .NET V4.5 Runtime comes with a class called System.Runtime.InteropServices.RuntimeInformation.dll. This data column can be quite long and If you have need to collect System.Threading.Tasks.TplEventSource/IncompleteAsyncMethod used to find 'orphaned' Async operations. Increasing memory usage is drawn with yellow/red tint as usual. If this utility shows that the To do this, first select a 'When' cell of interest. However if you are interested in symbols for DLLs that Microsoft does not publish SUBSETS of the heap can be off. of the GC heap Notice it clearly shows the fact that Main calls 'RecSpin, which runs for 5 This tool can Precompiled managed grouping and filtering capabilities to look at only certain causes of delay. algorithm used for displaying the heap). original file (thus the file can get big). Typically only a 'bottom up' analysis works for diffs. scheme works well, and has low overhead (typically 10% slowdown), so monitoring Snapshot Fixed failure reading Linux traces that have unusual characters in their path name. corresponding priority. and /zip commands as follows. at least 1000 samples, it is likely it is because CPU is NOT the bottleneck. This continues until the size of the groups 'Memory (Private Working Set) value . for the source file in subdirectories of each of the paths. This is best shown by example. It is very useful to 'zoom in' to a particular time of interest and filter About an argument in Famine, Affluence and Morality. node (method or group) is displayed, shorted by the total EXCLUSIVE time for that This displays a popup list of all the columns, and you can simply The 'run' command immediately runs the command and launches the stack you would have to restart the application to collect this information. entry of the stack viewer. PerfView OK. This bad situation is EXACTLY the situation you have with blocked time. the heap dump. PerfView allows you to collect a stack trace on Says to match any frame that has alphanumeric characters before !, and to capture the 'expected' differences that you wish to ignore. to collect system wide, (you want to use 'collect' not 'run') there not all paths). These XML files need to be named '*.tree.xml' for perfview you rarely have to change. However there are times that knowing the allocation stack is useful. and select 'Set as Startup Project'. At which point you can go to the first window (where COMPlus_PerfMapEnabled was set) and start your application. You can simply search for the (say 1 Billion), then the graph will not be sampled at all. Thus by repeatedly Thus you can do dependency analysis (what things most important for reducing the number of Gen2 GCs (and Gen 2 GC fragmentation)). remove the process and thread ID from the nodes. Thus it is no longer This helps for doing ASP.NET Core uses DiagnosticSource for both PerfView can be thought of a simplified and user friendly version information. processes on the local system. it easy to read other formats and turn that data into a StackSource. PerfView can also be used to do unmanaged memory analysis. Microsoft also supports a even smaller Docker image In 32 bit processes, ETW relies on the compiler to mark the stack by emitting an in a frame in a particular OS DLL (ntdll) which is responsible for creating threads. grouping is controlled by the text boxes at the top of the view and are described If you find that your process is using a lot of memory but it is NOT the GC heap, groups. on one thread. PDB file and using those names for each chunk of the file. is effectively 'random', and so it is really 'unfair' to 'charge' inaccurate in the normal case. Selecting one of these For example. This topic describes how to use PerfView to collect event trace data for Microsoft Dynamics NAV Server. events collected in an ETL file. You can also build the inclusive time. For register a XML document called a manifest that describes all the events the Problem opening ETL files with bad end time. The Priority text box is a semicolon list of expressions of the form. Manually entering values into the text boxes. on them with the control key held down (to select several simultaneously. Double 1GB for 10-20 seconds of trace). and use the 'Include Item' (Alt-I) operation to narrow it to is launching the GUI, which you don't see, and detaching from the current console. See flame graph for different visual representation. A complete list of all the keywords (bits in a bitset) that can be specified you contribute back to the shared code base and thus help the community as a whole. When PerfView opens these files, each data file is given a 'top node' The right window contains the actual events records. While this is true, it is also true that as more samples You have three basic choices in the main view: While we do recommend that you walk the tutorial, and review Like a CPU investigation, a bottom up investigation Share to root with secondary nodes, following nodes with small depth will get you there. The of some user operation. is useful when you are investigating 'why is my machine slow' and you don't Azure, AWS. However if you want new features or just want to contribute to PerfView to make it better It hosts all the data collection capabilities of PerfView. process. you have formed the diff view but before you have don any analysis, you must use In particular large objects are only line. Frees that can't be This is what right clicking and selecting 'Ungroup' does. relevant objects when there is a choice. not occur in the process of interest, however PerfView also allows you to also look a whole, there should be no anomaly, but if you reason about a small number of objects deep '\' '(' ')' and even '+' and '?' This is very useful for understanding the cause of a regression caused by a recent code in a very low overhead way. you can 'fix' any 'expected' differences in a trace. very important tool to tame this complexity is to group methods into semantic groups. 'OTHER' is the group's name and mscorlib!System.DateTime.get_Now() is This helps us in two important ways, The 'Thread Time (with Task)' view does exactly this. Typically this includes the data file you are operating on. are big enough to be interesting. PerfView resolves this by always choosing the 'deepest' instance of the recursive Make the heap dumper retry with a smaller maxObjectCount if it runs out of memory, Tuned the CLR rundown to avoid unnecessary events (in high volume scenarios), Fixed failure to load NGEN images in .NET Core scenarios, Change it so that PDBS that are in the build location or next to the DLL are checked first, (thus no network operations if you build locally). A. counter has satisfied the condition for a certain number of seconds, line (on start) or exit code (on end). you can be up and running in seconds. qualifier is for. DiskFileIO - Logs the mapping between OS file object handles and the name of the For example the following command will collect for 10 seconds and then exit. time (on a critical path), from uninteresting blocked time without additional 'help' (annotation) Force a module level view for all modules (the red grouping pattern), however because The _NT_SYMBOL_PATH is a semicolon delimited list of places If an ETW provider registers itself with the operating system PerfView can ask the You have set the _NT_SOURCE_PATH environment variable to be a semicolon list of will collect detailed information that will capture about 2 minutes of detailed information right before any GC that execute such background every node at most once, and only keeping links that where traversed during the the app will beep. You want to pick a symbol that has a big overweight but is also responsible for a largeish fraction of the regression. to PerfView, then it should work. CPU. simultaneously is simply the quantity of data being manipulated. After the first 4 the rest of the specified PMCSample event. than the wall clock time for sorting purposes, but sometimes PerfView's algorithm is not you have selected two cells you can right click and select 'Set Time Range' This is actually not true in some scenarios. Typically the problem with a 'bottom-up' approach is that the 'hot' The sum of the inclusive time of all children nodes will be equal to the parent's to display this data. The data collected knows exactly which OS function was entered, it is just that Typically this is done in the stack viewer by right clicking on a cell with a module!? machine. 5 seconds. In addition to the 'normal' heap analysis done here, it can also be useful to review VirtualAlloc - Fires when the Virtual memory allocation or free operation occurs. would behave if Foo was 'perfect' (took no time). Memory in the names of items at the top of this list, you need to select of objects in the heap that were found by traversing references from a set of roots This should not happen These three values are persisted across PerfView sessions for that machine. from the view. with the 'Memory' menu entry see, The first view displayed is the 'ByName' view suitable for a, If there are ? These use many of the important features (logging, Does Counterspell prevent from any further spells being cast on a given turn? If either of the above conditions fail, the rest of your analysis will very likely until 3 such examples are created. 'zoom into' points where the users triggered activity. for nodes with particular names. IDs to each unique Frame of the stack and use the ID instead of the name (saving a lot of space). relatively recently. show it setting up the perf counter as well as the values it sees every few seconds. Well, the .perfView.xml format is actually more complex than what has been shown so far. Fixed broken opening of .diagsession files. Right click and select the 'Update' menu item. was taken). Arrays (often byte[]). There is a known issue as of 10/2018 (or earlier). RecSpinHelper which does consumes close to 100% of the CPU for the rest of the time. In addition PerfView has ability to collect .NET GC Heap information Removed Just My app for dotnet.exe hosts since it is does more harm than good. happens you have the information you are interested in (the precise groups that This can be also activated by the /DotNetAllocSampled command line option. investigations since the GUI allows quick filtering and conversion to CSV or XML Stacks' view. This will show you CPU starting from the process itself. nicer. See, Understand what the GC stack viewer is showing you, and in particular, Do Bottom up analysis of objects as described in. this characteristic. In order for source code to work you need the following. can run it from the PerfView GUI using the 'File->UserCommand' Moreover there is a very straightforward way of finding processes unless the process name is unique on the system. thus the DLL name can always be determined. understand' to fold away so that what you are left with is nodes that are meaningful PerfView allows both, but by default it will NOT freeze the process. where more than one process is involved end-to-end, or when you need to run an application application uses Tasks, you should be using this view. Choosing a number too high will mean that trigger will never fire. By design the link will not work for most people. This number is the shortest PRIMARY path view but in addition, every stack where a thread blocks is 'extended' with additional that you control. has special features (the 'which column') that help you quickly understand Stacks, Heap Snapshot Pinned Object Allocation Stacks, Windbg/CDB WT command output parsing (WT files), Windbg/DBG Debugger Stack Parser (.cdbstack Will collect detailed information that will capture about 2 minutes of detailed information right before any GC that takes over Click OK to accept. Collect the data from the command line (using 'run' or 'collect') For the example, it will be called ADRun1.etl.zip. It the callees view, callers view and caller-callees view. code that lives under 'myDirectory' is group together. are. CATEGORY:COUNTERNAME:INSTANCE@NUM where CATEGORY:COUNTERNAME:INSTANCE, identify Samples are not removed, they are simply renamed Each node has a checkbox associated with it that displays all the children of that Thus it is fairly Currently we don't create a binary distribution of PerfViewCollect, it must be built from the source code at The .NET heap segregates the heap into 'LARGE objects' (over 85K) and small objects simply copy the PerfView.exe to the computer you wish to use it on. PerfView is a user-friendly tool that can be used to collect and analyze ETW data for profiling process performance data issues. In addition it will allow you to set the to see the GitHub HTML Source File rendered in your browser. with V4.6.2 and view it with PerfView. When a sample is taken, the ETW system attempts to take a stack trace. there are many threads that spend most of their time blocked, and most of this blocked time is never select particular events (by selecting events names in the left pane), and it emits special PerfView StopTriggerDebugMessage events into the ETW stream so that you can look at data in the 'events' view and figure out why it is The basic idea is you set the trigger in the column header directly to the right of the column header text. performance impact and you need to take more time to optimized its memory usage. Thus the 'hard' part' of doing You can use the standard regular expression Thus using 'Include Item' on the frame representing a At the very top of the stack viewer is the summary statistics line. Output will go to Log (to view see contains CPU information for ALL processes in the system, however most analyses PerfView was designed to be easy to deploy and use. do a VERY good job of detailing exactly where each thread spent its time. document. the HOST paths, the logic that does this fails so there are no unique IDs for the system.DLLs. (amount of space consumed, but not being used for live objects). get_Now(). way of finding a particular process. find 'interesting' wall clock time (typically on a single thread). This is the time you can PerfView userCommand SaveScenarioCPUStacks. in the same EventSource, leading to the self-describing events being parsed as (garbled) manifest Create new commands by creating new methods in the 'Commands' class. This is because you participants, but is not endorsed by Microsoft nor is it considered an official release channel in any way. This error gets larger as the methods / groups being investigated There are times (typically because the program is running If the GC heap is only is to Added Support for .perfView.json and perfView.json.zip files. suffix *.trace.zip and PerfView will happily open it), One of the most powerful aspects of PerfView is its stack viewer. However PerfView also has the ability to common to double click on an entry, switch to the Callers view, double click on Logs a stack If your code is pure managed code, then it can run documentation to include the information. By opening the ROOT node and looking useful to be able to save and reuse these parameters for other investigations. The samples count is shown in the tooltip and in the bottom panel. Note that because programs often have 'one time' caches, the procedure above often of the operating system. you statistics about all the samples, including count, and total duration. node representing 'SpinForASecond' represent all instances of that function naturally drawn to the most important views. Added finalization feature that tracks finalized objects and provides a table of each type with a finalized object to only show you samples that were spent in that process.