README
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Benchmark Profiling
Using benchmarks you can profile your programs and see exactly where your performance or memory is being taken.
Profiling Commands
CPU Profiling
Run the benchmark.
$ go test -run none -bench . -benchtime 3s -benchmem -cpuprofile cpu.out
Run the pprof tool.
$ go tool pprof benchmarks.test cpu.out
Run these pprof commands.
(pprof) list algOne
(pprof) web list algOne
Note that goroutines in "syscall" state consume an OS thread, other goroutines do not (except for goroutines that called runtime.LockOSThread, which is, unfortunately, not visible in the profile). Note that goroutines in "IO wait" state also do not consume threads, they are parked on non-blocking network poller (which uses epoll/kqueue/GetQueuedCompletionStatus to unpark goroutines later).
Memory Profiling
Run the benchmark.
$ go test -run none -bench . -benchtime 3s -benchmem -memprofile mem.out
Run the pprof tool.
$ go tool pprof -<PICK_MEM_PROFILE> benchmarks.test mem.out
Run these pprof commands.
(pprof) list algOne
(pprof) web list algOne
Documentation of memory profile options.
// Useful to see current status of heap.
-inuse_space : Allocations live at the time of profile ** default
-inuse_objects: Number of bytes allocated at the time of profile
// Useful to see pressure on heap over time.
-alloc_space : All allocations happened since program start
-alloc_objects: Number of object allocated at the time of profile
If you want to reduce memory consumption, look at the -inuse_space profile collected during normal program operation.
If you want to improve execution speed, look at the -alloc_objects profile collected after significant running time or at program end.
Code Review
Profiling (Go Playground) | Profiling Test (Go Playground)
All material is licensed under the Apache License Version 2.0, January 2004.
Documentation
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Overview ¶
Sample program that takes a stream of bytes and looks for the bytes “elvis” and when they are found, replace them with “Elvis”. The code cannot assume that there are any line feeds or other delimiters in the stream and the code must assume that the stream is of any arbitrary length. The solution cannot meaningfully buffer to the end of the stream and then process the replacement.
Source Files