github.com/powerman/golang-tools@v0.1.11-0.20220410185822-5ad214d8d803/cmd/benchcmp/doc.go (about)

     1  // Copyright 2014 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  /*
     6  
     7  Deprecated: benchcmp is deprecated in favor of benchstat: golang.org/x/perf/cmd/benchstat
     8  
     9  The benchcmp command displays performance changes between benchmarks.
    10  
    11  Benchcmp parses the output of two 'go test' benchmark runs,
    12  correlates the results per benchmark, and displays the deltas.
    13  
    14  To measure the performance impact of a change, use 'go test'
    15  to run benchmarks before and after the change:
    16  
    17  	go test -run=NONE -bench=. ./... > old.txt
    18  	# make changes
    19  	go test -run=NONE -bench=. ./... > new.txt
    20  
    21  Then feed the benchmark results to benchcmp:
    22  
    23  	benchcmp old.txt new.txt
    24  
    25  Benchcmp will summarize and display the performance changes,
    26  in a format like this:
    27  
    28  	$ benchcmp old.txt new.txt
    29  	benchmark           old ns/op     new ns/op     delta
    30  	BenchmarkConcat     523           68.6          -86.88%
    31  
    32  	benchmark           old allocs     new allocs     delta
    33  	BenchmarkConcat     3              1              -66.67%
    34  
    35  	benchmark           old bytes     new bytes     delta
    36  	BenchmarkConcat     80            48            -40.00%
    37  
    38  */
    39  package main // import "github.com/powerman/golang-tools/cmd/benchcmp"