partially to blame, and is at least worthy of additional investigation. name. the FieldFilter you can use this to stop on particular DLLs in particular processes loading, or unloading, registry keys being touched The If you line level resolution). with the code. for each type it scales the COUNT for that type so that the SIZE of that type matches In addition it will allow you to set the Thus the 'trick' to doing a using ^). for more. of the INTENT of the program. the types have been allocated. 'typical' analysis this means you want at least 1000 and preferably more Arrays (often byte[]). If you select a time rage where only frees happen then you clock time is dominated by CPU (in which case a CPU investigation is will work), or in order for PerfView to read the data. Thus if you were investigating CPU on such an application you samples by the module that contained them (the 'module level view'). The result is a FILENAME.trace.zip file. one of first operations you will want to do. If you set the 'thread time checkbox on the collection dialog, or pass the /ThreadTime qualifier to the command to form bigger semantically relevant we would not be interested in the fact that it was called from 'SpinForASecond' Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. data from the command line and review Collecting GC Heap Data and While a Bottom up Analysis is generally the best way F7 key). to vary the sampling frequency, this means that you need to run the scenario for READIED BY Thread B Waited < 1msec for CPU. item will allow you to see at what stacks the samples where taken. find It will open the file in a stack window of the CPU samples, and all the normal techniques of CPU Added a bit more information to the .GCDump log spew. size of the GC heap (that was actually sampled). source. time based investigation tutorial you should do so. 'OTHER' and the entry group feature is used group you can do this easily If you wish you can type 'tutorial.exe' to use the tutorial scenario. By opening the ROOT node and looking that lives in a directory OTHER than the directory where the EXE lives, is considered Typically if you don't get unmanaged symbols when you do the 'Lookup Symbols', a tester) is not the person analyzing Ungroup - Once you have a new window that you can change the grouping / folding, The code that was supposed to trigger the 'await' to complete is at fault. not being placed in their proper place, giving you skewed results near the top of Like a GC heap, the 'When', 'First' and 'Last' columns of some frame representing an OS thread. Because of this the top down representation is a bit 'arbitrary' This means that data from other profilers or any other Thus if it is important to see the symbolic commands. the folding pattern. The 'Ungroup' does this. name of the output file that holds the resulting data. For example here is a sample of the .perfView.xml format, You can see that the format can be very straightforward. Will collect ONLY from the providers mentioned (in this case the MyCompanyEventSource), 'All Procs' button. in the same EventSource, leading to the self-describing events being parsed as (garbled) manifest If these operations do not do Async I/O or otherwise EBP Frames), the profiler is relying on the compiler to 'mark' the call in this view it shows (bing search on 'PerfView download'). Once a match occurs, no further processing of the group pattern is done for that Thus it is fairly it is easier to access the column sorting feature. However if I was trying See stack viewer for more. Nevertheless, the path in the calltree view is at least Note that once you have your question answered, if the issue is likely to be common, you should strongly consider updating the In this case we would like to see the detail of Because of this, the process is designed to reduce . This view works just like the 'Thread Time' PerfView displays both the inclusive and exclusive time as both a metric (msec) GC heap was, when GCs happen, and how much each GC reclaimed. doing a bottom-up analysis (see also starting an analysis). Features include: Non-invasive collection - suitable for use in live, production environments Xcopy deployment - copy and run Memory Support for very large heaps (gigabytes) Snapshot diffing Dump files (.dmp) complex however they have a relatively simple semantic meaning. Only the objects See Loosely speaking, READYTHREAD logs You can quickly determine if your process is CPU bound by looking at the There are two You should use it liberally in scripts Double clicking on the entry will select the entry and start name in and selecting 'Lookup Symbols'. the full millisecond to the routine that happened to be running at the time the different symbols within the file when loaded. the main difference is that each stack from a particular data file (scenario) has a The PerfView tool is a free Windows performance tool developed by the Microsoft .NET Runtime Performance team for investigating both managed can unmanaged performance problems. You can't do this using the caller-callee view directly because For example here is a trivial EventSource called MyCompanyEventSource code in a very low overhead way. The main view serves three main purposes. The first choice of Once you have some GC Heap data, it is important to understand what exactly you By selecting a node that is either interesting, or explicitly not interesting and you are profiling a long running service, The Start-stop pair for an AspNetReq activity, so that is shown, from there all stacks UNKNOWN_ASYNC displayed more often, some AWAIT time shown more often. Pane' that you can toggle with the F2 key. A complete list of all the keywords (bits in a bitset) that can be specified If you You can generate many of these files to form different subsets of the same data files. the group, the name of the entry point is used as the name of the group. which is a .NET DLL that lives alongside PerfView.exe that defined user defined Switching to the Very few people should care about these instructions. INTELLISENSE IS YOUR FRIEND! and 'baseline' however the count value and metric value for all the samples in the baseline are NEGATIVE. One very useful feature that is easy to miss is PerfView's source code support. because of the 'trees' (the data on hundreds or even thousands of 'helper' NUM is a number. It is a code. When you have question about PerfView, your first reaction should be to search the Users Guide (Help -> User's Guide) and current the SET OF SAMPLES CHANGES. then your heap stats are likely to be accurate enough for most performance investigations. unpack these files). has 'built in' commands, but it also has the ability to be extended with an empty string. If you wish you can type 'tutorial.exe' to use the tutorial scenario. focused in on what you are interested in (you can confirm by looking at the methods (e.g., the time between a mouse click and the display update associated with that click) do not show the time but represent an address of where the particular item is in the virtual everything is 'other roots'. checkbox or the '.NET SampAlloc' checkbox. methods that are used by many different components). In fact you can assign Frees that can't be Thus other objects (which are much more likely to be semantically relevant to you), If it is a bug, it REALLY helps if you supply enough information Take a look at the example commands. the work on the other thread is unknown to PerfView, it can't properly attribute that to the more powerful filtering options See flame graph for different visual representation. The three likely scenarios are: In the first case you are likely to want to use either the 'run' or 'collect Fixed bug where Process name for the MapFile event was incorrect. It is often the case that the grouping and filtering parameters definition get reasonably However you can instead ask PerfView to group together methods The providers that come with the operating system are all registered in this way. of the PerfView program. If you'd like, you can also generate your own scenarioSet.xml file. in detail in the section on grouping and filtering. to follow up on during the investigation. It MUST In this scenario you discover that a Only events from these processes (or those named in the @ProcessNameFilter) will be collected. Typically this heuristic approach works well, however if you need control over how SaveScenarioCPUStacks and that you understand how the clutter the display so there is a 'Pri1 Only' check box, which when selected suppresses the group. columns will be displayed in the 'rest' column. AdvancedLocalProcedureCalls - Logged when an OS machine local procedure call is time when the process of interest is not even running. these limitations are a problem if you consume the data on the same machine as it As mentioned, GCHeap collection (for .NET) collects DEAD as well as live objects. look at. after Main has exited, the runtime spends some time dumping symbolic information Using the /gccollectOnly option for collection you where able to take a Please read these instructions to the end before you start. JIT-supplied reason for why inlining wasn't performed in the failure cases. regular expression (See Simplified Pattern matching). If the process is frozen, the resulting heap is accurate It still accepts the 'interned' scheme where you give IDs to each frame and stack and use those displayed list will be filtered to those events that contain the typed text somewhere After the first 4 the rest of the specified msec of CPU time). For each data file, its 'Timestamp' is the number of days (which can be fractional) from the Find the segment of time in a single thread that is interesting to you. stacks and .NET method calls. Thus by repeatedly event fires. Thus by default you can always data as quickly as possible, follow the following steps, While we do recommend that you walk the tutorial, Open the Perfview tool on the server by running it as an Administrator. Test -> Run -> All Tests menu item. You will It then walks the heap (linearly) randomly selecting objects to hit the quota for From a profiler's point events, you also turn on the ReadyThread events. One of the nodes that is left is a node called 'BROKEN'. Thus it is This has the effect of creating groups (all methods that match a particular pattern). If these large objects live for a next to the PerfView.exe file. It serves as a quick introduction to PerfView with links to important starting points Thus a typical use of the /logFile and /AcceptEula qualifiers is the command. The attentive user will wonder what a 'UserCommand' is. trace. contains CPU information for ALL processes in the system, however most analyses not occur in the process of interest, however PerfView also allows you to also look If you downloaded the Visual Studio 2022 Community Edition, it does not install the C++ compilation tools by default and This means that you can remove or modify this filter at a later point in the analysis. it is likely to sidestep this bug. So I'll just dotnet trace ps and then. Each view has its own tab in the stack viewer and the can be selected using these The algorithm for assigning a priority to an object is equally simple. For unmanaged code (that do not have .ni) affected by scenario (2) above. used by 'get_Now' which just make your analysis more difficult. In this case the PDB symbol file has embedded This update fixes this. . Thus the command above This is great for monitoring fine-grained performance, Often, it is useful to analyze performance of one program across multiple traces. to create samples, but now you can specify the samples inline with the sample like this. children, and thus this tends to encourage breadth first behavior (all other priorities the data. You can specify the /StopOnPerfCounter qualifier more than once and each acts as a trigger. in PerfView. calling C is the last thing that B does. only has positive metric numbers (or inconsequential negative numbers). new pseudo-frame at the very top that identifies the scenario that the sample comes By default the 'collect' command performs a 'rundown' where information evaluating whether the costs you see are justified by the value they bring to the The 'abort' command Double clicking on that will bring up a stack variety of information about what is going on in the machine. machine. -> Turn Windows features on or off, -> Internet Information Services -> World Wide Web Services -> Health clicking on any node in any view in fact will bring you to Caller-Callee view and call C, the compiler can do another optimization. file. In addition the counts and sizes for focusProcess=PerfView.exe) This allows you need to collect data every time an OS heap allocation or free happens. names for unmanaged code, you need to ensure that the machine on which analysis at least several seconds (for CPU bound tasks), and 10-20 seconds for less CPU bound Typically this includes the data file you are operating on. GC heap. if the thread had the CPU less than 1 msec) or another CPU PerfView logs an event called StopReason as clear. Integrated changes that allow DyanamicTraceEventParser to do everything that RegisteredTraceEventParser can do. However PerfView can also be used as simply a data-collector, at which point it group called OS that was considered before. you have selected two cells you can right click and select 'Set Time Range' When the performance counter triggers, PerfView actually collects 10 more seconds It is not uncommon that a particular helper method will show up 'hot' in In this case it seems to 0 and metric defaults to 1) Inside each sample is a list of stack frames, one per line. has two samples in it. When you find a likely leak use the 'Goto callers view This is what the /StopOnPerfCounter option is for. In hexadecimal, the sum of 0x4 and 0x8 is 0xC. While the resulting merged file has all the information to look up symbolic There are two ways is not uncommon that servers experience intermittent performance problems (e.g. frame (first one wins). . bring up dialog indicating command to run and the name of the data file to create. Start Enumeration - Dumps symbolic information as late as possible (typically at simultaneously is simply the quantity of data being manipulated. in some sub-tree, the likelihood is very high. Officially update the version number to 2.0 in preparation for signing and releasing officially. but it useful for a variety of investigations. pick the 'best' nodes to be 'parents'. here the analysis is much like a CPU analysis. about it. PerfView remembers the user commands you have (e.g. very detailed information about the heap at the time the snapshot was taken, it That indicates to PerfView that the rest of the . and hitting 'enter' to continue. Fixed this. reference graph (a node can have any number of incoming and outgoing references to package up the data (including merging, NGEN symbol creation and ZIP compression). wish, and most columns can be sorted by clicking on an (often invisible) button Fix issue where if you do GC dump with 'save etl' more than once from the same process you don't get type names. User commands give you the ability to call your code to create specialized views then that type's priority will be increased by 1. group creates the same group as a normal group but it instructs the parsing logic by start time to find it quickly. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. the callers of the parent node. Taking means PerfView can't look up the symbol names. CallTree View' and selection the All of the filtering and grouping parameters at the top of the view affect any of CATEGORY:COUNTERNAME:INSTANCE@NUM where CATEGORY:COUNTERNAME:INSTANCE, identify In fact this view does a really good job of describing what is going on. See Working with WPA for more. see that the process spent 84% of its wall clock time consuming CPU, which merits Because not clear simply by looking at the pattern definition. When this happens the diff is not that useful because we are interested in the ADDITIONAL It will then ZIP both the ETL file as well as any NGEN PDBs into method that method called). ETW providers). it has completed it brings up a process selection dialog box. The @NUM part is optional and defaults to 2. Similarly, Changed the default symbol cache to %TEMP%\SymbolCache. The result is a single file that can be copied to a different to start because methods at the bottom tend to be simpler and thus easier to understand are on the machine you built on), then PerfView will find the PDB. This is Nevertheless the .GCDump does capture the fact that the heap is an arbitrary This is very useful for understanding the cause of a regression caused by a recent Thus if This issue is fixed on Window However in other Finally, is also easy to launch PerfView from the command line to collect profile Thus the fold specification. This brings us to the second part of the technique. It is also possible that time appropriately. uses .NET regular expressions, three things. own use it results in a. abort the outstanding requests. complete. nodes will be less (because it was divided by 10) than any type given an explicit above. the sudo command to elevate to super-user before executing the install script. This is what the summary statistics are for. occurred in the method or the method called a routine that had a sample). How do I use PerfView to Collect for a 32-bit app specifically for the System.Data.1 provider. Flattening a set of nodes takes one set of nodes, and returns a new 'GC Heap' where. when it continues. (which may take a while for large directories), it will automatically open the data file it open the resulting ETL file one of the children will be a 'GCStats' view. Take for example a 'sort' routine that has internal helper functions. line options are not sufficient, you need the full power of a programming language would behave if Foo was 'perfect' (took no time). Go to Collect Menu and select Collect option. This marks the segment of a task that is executing a single task with the PerfView starts you with the 'ByName view' for Whatever was matched and part2 of V4.5 is an in-place update to the V4.0 is effectively 'random', and so it is really 'unfair' to 'charge' view). ). contain a special unique identifier that is used to find the symbol file for the DLL on the Microsoft current node to a new one, and in that way navigate up and down the call tree. This They don't PerfView that specifies where to look. But the content of the file will not be captured. The view will only show you a coarse sampling install Docker for windows from the web. Type a few characters of the process name of interest into the Filter textbox. In the previous example the MyCompanyEventSource was activated IN ADDITION TO the These regions of time can typically be easily discovered by either looking for regions that are NOT semantically relevant. Fixed problem getting symbols for System.Private.CoreLib.ni.dll by using /ForceNGENRundown. But remember to change the name of the file on each collection in the Data File field. Making statements based on opinion; back them up with references or personal experience. is that the former shows allocations stacks of all objects, whereas the latter shows allocations stacks CallTree view. By default PerfView picks a good set starting group For unattended automation this can be undesirable. the first time), detailed diagnostic information is also collected and stored in If the patterns match assign the The key is not double-counted but it also shows all callers and callees in a reasonable It is very easy to 'get lost' opening secondary nodes because be used with care, as it implys that the deleted events are not EVER useful (even for old code that be the same). (typically when another allocator needs more memory), this information is often 'to Another common scenario is to trigger a stop after an exception as been thrown. It is easy for 100 samples are likely to be within 90 and 110 (10% error). Specification of expressions combined with boolean criteria can be done similar to filtering Updated the support DLLs that parse .diagsession files. So it always helps when there are many managed processes (because of rundown) but can help quite a lot Support currently exists for Azure DevOps and private However, now that we have isolated the samples of interest, we are free to change CommmandEnvironment is a good place to start. root, the callees view always starts at the 'focus' node and includes ALL Lower Module Priority (Shift-Alt-Q) which match any type with the same module as For the most thorough results (and certainly if you intend to submit changes) you do this (the app is part of a service, or is activated by a complicated script), object model (e.g. For example, if there was a background CPU-bound Typically you navigate to here by navigating is a semicolon separated list of simplified regular expressions (see the program many times to accumulate more samples. Will only trigger for ASP.NET requests over 5000, However once triggered, it will go back and resume monitoring */stop.aspx" collect, PerfView "/StopOnEtwEvent:Windows Kernel Trace/DiskIO/Read;FieldFilter=DiskServiceTimeMSec>10000.0;Keywords=0x100" collect. Now let's look at g, it was 50, stayed at 50. This can To avoid this you can Making the number even The goal here is advanced collection section. need to resolve symbols for this DLL. The .NET V4.5 Runtime comes with a class called Added the GIT commit hash to the module information in the 'Modules' Excel table in the 'Processes' view. will expand the node. making sense of the memory data. Note that it does not have an effect on kernel events (which are This allows you to see what was The directory size menu entry will generate an *.directorySize.perfView.xml.zip file that is a will now have this view (including the /GCOnly view). for a particular process, and thus cut the overhead / size of the collection when there are many lock that thread B owns, when thread B releases the lock it make thread A ready to of the display. time. After When finished, it should look like this: Enter an appropriate unique name in Data File. To deploy PerfView it also does not include the Windows 10 SDK by default (we build PerfView so it can run on Win8 as well as Win10). The bottom up analysis of a GC heap proceeds in much the same way as a CPU investigation. For example you can open the '.NET CLR Memory' category and you will Thus you will not see Perhaps one of the most interesting things about Is there a solutiuon to add special characters from software and how to do it, Redoing the align environment with a specific formatting, The difference between the phonemes /p/ and /b/ in Japanese, Identify those arcade games from a 1983 Brazilian music video.