norace_test.go

Documentation: runtime

		 1  // Copyright 2013 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  // The file contains tests that cannot run under race detector for some reason.
		 6  //go:build !race
		 7  // +build !race
		 8  
		 9  package runtime_test
		10  
		11  import (
		12  	"runtime"
		13  	"testing"
		14  )
		15  
		16  // Syscall tests split stack between Entersyscall and Exitsyscall under race detector.
		17  func BenchmarkSyscall(b *testing.B) {
		18  	benchmarkSyscall(b, 0, 1)
		19  }
		20  
		21  func BenchmarkSyscallWork(b *testing.B) {
		22  	benchmarkSyscall(b, 100, 1)
		23  }
		24  
		25  func BenchmarkSyscallExcess(b *testing.B) {
		26  	benchmarkSyscall(b, 0, 4)
		27  }
		28  
		29  func BenchmarkSyscallExcessWork(b *testing.B) {
		30  	benchmarkSyscall(b, 100, 4)
		31  }
		32  
		33  func benchmarkSyscall(b *testing.B, work, excess int) {
		34  	b.SetParallelism(excess)
		35  	b.RunParallel(func(pb *testing.PB) {
		36  		foo := 42
		37  		for pb.Next() {
		38  			runtime.Entersyscall()
		39  			for i := 0; i < work; i++ {
		40  				foo *= 2
		41  				foo /= 2
		42  			}
		43  			runtime.Exitsyscall()
		44  		}
		45  		_ = foo
		46  	})
		47  }
		48
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