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Use Getpid and SchedGetaffinity from golang.org/x/sys/unix to get the number of CPUs in numCPU on Linux. Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
33 lines
696 B
Go
33 lines
696 B
Go
package sysinfo // import "github.com/docker/docker/pkg/sysinfo"
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import (
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"runtime"
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"golang.org/x/sys/unix"
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)
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// numCPU queries the system for the count of threads available
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// for use to this process.
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//
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// Issues two syscalls.
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// Returns 0 on errors. Use |runtime.NumCPU| in that case.
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func numCPU() int {
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// Gets the affinity mask for a process: The very one invoking this function.
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pid := unix.Getpid()
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var mask unix.CPUSet
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err := unix.SchedGetaffinity(pid, &mask)
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if err != nil {
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return 0
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}
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return mask.Count()
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}
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// NumCPU returns the number of CPUs which are currently online
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func NumCPU() int {
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if ncpu := numCPU(); ncpu > 0 {
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return ncpu
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}
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return runtime.NumCPU()
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}
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