Net/tcp: question for SetKeepAlivePeriod and roundDurationUp

11153 · January 24, 2020, 5:35am

Hi all.
Few days ago, I tried to use TCPConn.SetKeepAlivePeriod and I found this code

golang/go/blob/8d7be1e3c9a98191f8c900087025c5e78b73d962/src/net/tcpsockopt_unix.go#L15-L17


func setKeepAlivePeriod(fd *netFD, d time.Duration) error {
	// The kernel expects seconds so round to next highest second.
	secs := int(roundDurationUp(d, time.Second))

github.com

golang/go/blob/8d7be1e3c9a98191f8c900087025c5e78b73d962/src/net/tcpsock.go#L341-L344


// roundDurationUp rounds d to the next multiple of to.
func roundDurationUp(d time.Duration, to time.Duration) time.Duration {
	return (d + to - 1) / to
}

As I understand this code, if I pass 1.6 second to roundDurationUp, result must be 2.
If I pass 1.4 second to roundDurationUp, this must be 2 also.

But something strange, isn’t it?
This method work as ceil function not a round function.

How do you think?

calmh · January 24, 2020, 3:16pm

“Round up” is another way to say “ceil”.

11153 · January 26, 2020, 11:08pm

Thanks!

system · April 25, 2020, 11:08pm

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