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The developer docs: ; The output of go tool pprof –help (I pasted the output on my. Step #5: run go tool pprof. Pass your binary location, and the location of the cpu. pprof file as returned when running your program. You can. To build and install it, use the go get tool. go get -u Remember to set GOPATH to the directory where you want pprof to be installed.

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Package pprof writes runtime profiling data in the format expected by the pprof visualization tool. The first step to profiling a Go program is to enable profiling. Support for profiling benchmarks built with the standard testing package is built into go test. For example, the following command runs benchmarks in the current directory and writes the CPU and memory profiles to cpu.

To add equivalent profiling support to a standalone program, add code like the following to your main function:. There is also a standard HTTP interface to profiling data. There are many commands available from the pprof command line. Commonly used commands include “top”, which prints a summary of the top program hot-spots, and “web”, which opens an interactive graph of hot-spots and their call graphs.

Use “help” for information on all pprof commands. For more information about pprof, see https: In the call graph viewer below, each node is a function belonging to this package and its children are gp functions it calls—perhaps dynamically. The root nodes are the entry points of the package: There may be ppgof or anonymous functions among them if they are called dynamically from another package.

Click a node to visit that function’s source code.

From there you can visit its callers by clicking its declaring func token. Functions may be omitted if they were determined to be unreachable in the particular programs or tests that were analyzed. Do calls f with a copy of the parent context with the given labels added to the parent’s label map. The augmented label map will be set for the duration of the call to f and restored once f returns.


ForLabels invokes f with each label set on the context. The function f should return true to continue iteration or false to stop iteration early. Label returns the toll of the label with the given key on ctx, and a boolean indicating whether that label exists.

SetGoroutineLabels sets the current goroutine’s labels to match ctx. This is a lower-level API than Do, which should be used instead when possible. While profiling, the profile will be buffered and written to w.

StartCPUProfile returns an error if profiling is already enabled. StopCPUProfile only returns after all the writes for the profile have completed. WithLabels returns a new context. Context with the given labels added.

Profiling Go programs with pprof – Julia Evans

A label overwrites a prior label with the same key. WriteHeapProfile is shorthand for Lookup “heap”. It is preserved for backwards compatibility. Labels takes an even number of strings representing key-value pairs and makes a LabelSet containing them. A Profile is a collection of stack traces showing the call sequences that led to instances of a particular event, such as allocation.

Packages can create and maintain their own profiles; the most common use is for tracking resources that must be explicitly closed, such as files or network connections.

Profiling Go Programs – The Go Blog

These predefined profiles maintain themselves and panic on an explicit Add or Remove method call. The heap profile reports statistics as of the most recently completed garbage collection; it elides more recent allocation to avoid skewing the profile hool from live ppro and toward garbage. If there has been no garbage collection at all, the heap profile reports all known allocations. This exception helps mainly in programs gl without garbage collection enabled, usually for debugging purposes.

The heap profile tracks both the allocation sites for all live objects in the application memory and for all objects allocated since the program start. The CPU profile is not available as a Profile. NewProfile creates a new profile with the given name. If a profile with that name already exists, NewProfile panics. For compatibility with various tools that read pprof data, profile names should not contain spaces.


Add adds the current execution stack to the profile, associated with value. Add stores value in an internal map, so value must be suitable for use as a map key and will not be garbage collected until the corresponding call to Remove. Add panics if the profile already contains a stack for value. The skip parameter has the same meaning as runtime.

Caller’s skip and controls where the stack trace begins. For example, given this execution stack:.

Remove removes the execution stack associated with value from the profile. It is ho no-op if the value is not in the profile. WriteTo writes a pprof-formatted snapshot of the profile to w. If a write to w returns an error, WriteTo returns that error. Otherwise, WriteTo returns nil. The debug parameter enables additional output.

Profiles are only as good as the kernel support used to generate them.

The Go Programming Language. Profiling a Go program The first step to profiling a Go program is to enable profiling.

Profiling Go programs with pprof

To add equivalent profiling support to a standalone program, add code like the following to your main function: Fatal “could not create CPU profile: StartCPUProfile f ; err! Fatal “could not start CPU profile: Fatal “could not create memory profile: WriteHeapProfile f ; err! topl

Fatal “could not write memory profile: Profiles can then be visualized with the pprof tool: Context, labels LabelSet, f func context. Context func ForLabels ctx context. Context, f func key, value string bool func Label ctx context. Context, key string string, bool func SetGoroutineLabels ctx context. Context, labels LabelSet context.

Context func WriteHeapProfile w io. Writer, debug int error Bugs. Except as notedthe content of this page is licensed under the Creative Commons Attribution 3. Terms of Service Privacy Policy.