57 lines
1000 B
Go
57 lines
1000 B
Go
package parallel
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import (
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"runtime"
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"sync"
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)
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// Execute process in parallel the work function
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func Execute(nbIterations int, work func(int, int), maxCpus ...int) {
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nbTasks := runtime.NumCPU()
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if len(maxCpus) == 1 {
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nbTasks = maxCpus[0]
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if nbTasks < 1 {
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nbTasks = 1
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} else if nbTasks > 512 {
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nbTasks = 512
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}
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}
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if nbTasks == 1 {
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// no go routines
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work(0, nbIterations)
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return
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}
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nbIterationsPerCpus := nbIterations / nbTasks
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// more CPUs than tasks: a CPU will work on exactly one iteration
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if nbIterationsPerCpus < 1 {
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nbIterationsPerCpus = 1
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nbTasks = nbIterations
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}
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var wg sync.WaitGroup
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extraTasks := nbIterations - (nbTasks * nbIterationsPerCpus)
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extraTasksOffset := 0
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for i := 0; i < nbTasks; i++ {
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wg.Add(1)
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_start := i*nbIterationsPerCpus + extraTasksOffset
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_end := _start + nbIterationsPerCpus
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if extraTasks > 0 {
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_end++
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extraTasks--
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extraTasksOffset++
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}
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go func() {
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work(_start, _end)
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wg.Done()
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}()
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}
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wg.Wait()
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}
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