introduce obidefault

pkg/obidefault/workers.go

@@ -0,0 +1,170 @@
+package obidefault
+
+import "runtime"
+
+var _MaxAllowedCPU = runtime.NumCPU()
+var _WorkerPerCore = 1.0
+
+var _ReadWorkerPerCore = 0.25
+var _WriteWorkerPerCore = 0.25
+
+var _StrictReadWorker = 0
+var _StrictWriteWorker = 0
+
+var _ParallelFilesRead = 0
+
+// CLIParallelWorkers returns the number of parallel workers used for
+// computing the result.
+//
+// The number of parallel workers is determined by the command line option
+// --max-cpu|-m and the environment variable OBIMAXCPU. This number is
+// multiplied by the variable _WorkerPerCore.
+//
+// No parameters.
+// Returns an integer representing the number of parallel workers.
+func ParallelWorkers() int {
+	return int(float64(MaxCPU()) * float64(WorkerPerCore()))
+}
+
+// CLIMaxCPU returns the maximum number of CPU cores allowed.
+//
+// The maximum number of CPU cores is determined by the command line option
+// --max-cpu|-m and the environment variable OBIMAXCPU.
+//
+// No parameters.
+// Returns an integer representing the maximum number of CPU cores allowed.
+func MaxCPU() int {
+	return _MaxAllowedCPU
+}
+
+func MaxCPUPtr() *int {
+	return &_MaxAllowedCPU
+}
+
+// WorkerPerCore returns the number of workers per CPU core.
+//
+// No parameters.
+// Returns a float64 representing the number of workers per CPU core.
+func WorkerPerCore() float64 {
+	return _WorkerPerCore
+}
+
+// SetWorkerPerCore sets the number of workers per CPU core.
+//
+// It takes a float64 parameter representing the number of workers
+// per CPU core and does not return any value.
+func SetWorkerPerCore(n float64) {
+	_WorkerPerCore = n
+}
+
+// SetMaxCPU sets the maximum number of CPU cores allowed.
+//
+// n - an integer representing the new maximum number of CPU cores.
+func SetMaxCPU(n int) {
+	_MaxAllowedCPU = n
+}
+
+// SetReadWorker sets the number of workers for reading files.
+//
+// The number of worker dedicated to reading files is determined
+// as the number of allowed CPU cores multiplied by number of read workers per core.
+// Setting the number of read workers using this function allows to decouple the number
+// of read workers from the number of CPU cores.
+//
+// n - an integer representing the number of workers to be set.
+func SetStrictReadWorker(n int) {
+	_StrictReadWorker = n
+}
+
+func SetStrictWriteWorker(n int) {
+	_StrictWriteWorker = n
+}
+
+// SetReadWorkerPerCore sets the number of worker per CPU
+// core for reading files.
+//
+// n float64
+func SetReadWorkerPerCore(n float64) {
+	_ReadWorkerPerCore = n
+}
+
+func SetWriteWorkerPerCore(n float64) {
+	_WriteWorkerPerCore = n
+}
+
+// ReadWorker returns the number of workers for reading files.
+//
+// No parameters.
+// Returns an integer representing the number of workers.
+func StrictReadWorker() int {
+	return _StrictReadWorker
+}
+
+func StrictWriteWorker() int {
+	return _StrictWriteWorker
+}
+
+// CLIReadParallelWorkers returns the number of parallel workers used for
+// reading files.
+//
+// The number of parallel workers is determined by the command line option
+// --max-cpu|-m and the environment variable OBIMAXCPU. This number is
+// multiplied by the variable _ReadWorkerPerCore.
+//
+// No parameters.
+// Returns an integer representing the number of parallel workers.
+func ReadParallelWorkers() int {
+	if StrictReadWorker() == 0 {
+		n := int(float64(MaxCPU()) * ReadWorkerPerCore())
+		if n == 0 {
+			n = 1
+		}
+		return n
+	} else {
+		return StrictReadWorker()
+	}
+}
+
+func WriteParallelWorkers() int {
+	if StrictWriteWorker() == 0 {
+		n := int(float64(MaxCPU()) * WriteWorkerPerCore())
+		if n == 0 {
+			n = 1
+		}
+		return n
+	} else {
+		return StrictReadWorker()
+	}
+}
+
+// ReadWorkerPerCore returns the number of worker per CPU core for
+// computing the result.
+//
+// No parameters.
+// Returns a float64 representing the number of worker per CPU core.
+func ReadWorkerPerCore() float64 {
+	return _ReadWorkerPerCore
+}
+
+func WriteWorkerPerCore() float64 {
+	return _ReadWorkerPerCore
+}
+
+// ParallelFilesRead returns the number of files to be read in parallel.
+//
+// No parameters.
+// Returns an integer representing the number of files to be read.
+func ParallelFilesRead() int {
+	if _ParallelFilesRead == 0 {
+		return ReadParallelWorkers()
+	} else {
+		return _ParallelFilesRead
+	}
+}
+
+// SetParallelFilesRead sets the number of files to be read in parallel.
+//
+// n - an integer representing the number of files to be set.
+func SetParallelFilesRead(n int) {
+	_ParallelFilesRead = n
+}