Mercurial > hg > CbC > CbC_gcc
view libgo/go/testing/allocs.go @ 158:494b0b89df80 default tip
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author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Mon, 25 May 2020 18:13:55 +0900 |
parents | 04ced10e8804 |
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// Copyright 2013 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package testing import ( "runtime" ) // AllocsPerRun returns the average number of allocations during calls to f. // Although the return value has type float64, it will always be an integral value. // // To compute the number of allocations, the function will first be run once as // a warm-up. The average number of allocations over the specified number of // runs will then be measured and returned. // // AllocsPerRun sets GOMAXPROCS to 1 during its measurement and will restore // it before returning. func AllocsPerRun(runs int, f func()) (avg float64) { defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1)) // Warm up the function f() // Measure the starting statistics var memstats runtime.MemStats runtime.ReadMemStats(&memstats) mallocs := 0 - memstats.Mallocs // Run the function the specified number of times for i := 0; i < runs; i++ { f() } // Read the final statistics runtime.ReadMemStats(&memstats) mallocs += memstats.Mallocs // Average the mallocs over the runs (not counting the warm-up). // We are forced to return a float64 because the API is silly, but do // the division as integers so we can ask if AllocsPerRun()==1 // instead of AllocsPerRun()<2. return float64(mallocs / uint64(runs)) }