Hi Ian, Thanks for clarifying, yes it's no harm to leave the code untouched.
On Tuesday, August 15, 2023 at 3:21:57 AM UTC+8 Ian Lance Taylor wrote: > On Mon, Aug 14, 2023 at 11:28 AM metronome <xiangd...@gmail.com> wrote: > > > > >> If several different goroutines decide to wake up the polling > > >> goroutine before the polling goroutine wakes up, they will each write > > >> a single byte > > > > Wondering, with the introduction of "netpollWakeSig", does it still hold > true? Thanks. > > Good point, I think you're right. With netpollWakeSig we shouldn't > expect to see more than a single byte written to the pipe. > > Doesn't hurt to try to read more bytes, though. > > Ian > > > On Tuesday, July 11, 2023 at 9:00:36 AM UTC+8 Ian Lance Taylor wrote: > >> > >> On Mon, Jul 10, 2023 at 6:10 AM shaouai <aou...@gmail.com> wrote: > >> > > >> > In the implementation of the Go netpoller, `netpollBreak()` attempts > to write 1 byte to `netpollBreakWr`, whereas `netpoll()` reads up to 16 > bytes from `netpollBreakRd`, why 16 bytes rather than 1 byte? > >> > > >> > write up to 1 byte: > https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/runtime/netpoll_epoll.go;l=77;drc=c7cc2b94c63af610a29b1b48cfbfb87cb8abf05b > >> > > >> > read up to 16 bytes: > https://cs.opensource.google/go/go/+/refs/tags/go1.20.5:src/runtime/netpoll_epoll.go;l=146;drc=c7cc2b94c63af610a29b1b48cfbfb87cb8abf05b > >> > >> A single byte will wake up a goroutine sleeping in netpoll, so there > >> is no reason to write more than one byte. > >> > >> If several different goroutines decide to wake up the polling > >> goroutine before the polling goroutine wakes up, they will each write > >> a single byte, and they will all be satisfied by a single wakeup. > >> And, if we don't read all those bytes, there will still be bytes in > >> the pipe and we'll wake up the next time around the poll loop even if > >> we don't have to. So we try to read all of their wakeup bytes at > >> once. The number 16 is arbitrary, based on the assumption that it's > >> not all that likely that more than 16 goroutines will try to wake up > >> the poller simultaneously. > >> > >> Ian > > > > -- > > You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to golang-nuts...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/8a3ae80e-1e78-441d-8c9a-c99e94e3c2c9n%40googlegroups.com > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/6a42744a-6c3f-4039-99f2-2f6e993fad52n%40googlegroups.com.
