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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Profiling Go Programs – The Go Blog

For more information about pprof, see https: It was generating these heap profiles named like pprof. In the one remaining case, we can write a simple variant of the append built-in function:. I ppof an even simpler Go program to get the simplest possible heap profile. Writer, debug int error Bugs. Every time FindLoops is called, it allocates some sizable bookkeeping structures.

Init currentNode, current 1 37 The third column shows the running total during the listing: To add equivalent profiling support to a standalone program, add code like the following to your main function:.

The root nodes are the pprod points of the package: It has a lot of useful comments!


If your application is not already running an http server, you need to start one. WriteHeapProfile f ; err! The profile has samples, so it was running for a bit over 25 seconds.

All toop these kinds of profiles goroutine, heap allocations, etc are just collections of stacktraces, maybe with some metadata attached.

The first three columns are the number of samples taken while running that line, the number of samples taken while running that line or in code called from that line, and the line number in the file. The package is typically only imported for the side effect of registering its HTTP handlers. So the stack traces in the heap profile might be for code that is not running anymore — like maybe a function allocated a bunch of memory, returned, and a different function that should be freeing that memory is misbehaving.

Just as they would be in a compiler, the basic block structures have unique sequence numbers assigned to them. For now, we are making the minimal possible changes in order to understand what is important for the performance of our program; this change is simple and mirrors the code in the Java implementation.

Changing number from a map to a slice requires editing seven lines in the program and cut its run time by nearly a factor of two:. Click a node to visit that function’s source code. If the tol used the Go testing package ‘s benchmarking support, we could use gotest’s standard -cpuprofile and -memprofile flags.


Profiling Go programs with pprof

Now memory allocation and the consequent garbage collection runtime. A sample is basically a stack trace. Profiles can then be visualized with the pprof tool: Terms of Service Privacy Policy View the source code.

There are many commands available from the pprof command line. If we list FindLoops we can see that much of it is right at the beginning:. I think how the heap profiles work is — allocations are recorded at some sample rate. That stack trace might have some extra information attached to it! Now that we have a rough idea of the big picture, it’s time to zoom in on a particular function.

Profiling Go programs with pprof – Julia Evans

Pprov as notedthe content of this page is licensed under the Creative Commons Attribution 3. Use “help” for information on all pprof commands. If there has been no garbage collection at all, the heap profile reports all known allocations. A few profiles are predefined: