On 07/10/2013 04:18 PM, Eliezer Tamir wrote: > Add description for the SO_BUSY_POLL socket option to the socket(7) manpage. Long after the fact, I've applied this. Thanks, Eliezer. Would you be willing also to write a patch for the POLL_BUSY_LOOP flag of poll()? Cheers, Michael > v2 > fixed typos reported by Rasmus Villemoes > > Signed-off-by: Eliezer Tamir <eliezer.tamir@xxxxxxxxxxxxxxx> > --- > > man7/socket.7 | 25 +++++++++++++++++++++++++ > 1 files changed, 25 insertions(+), 0 deletions(-) > > diff --git a/man7/socket.7 b/man7/socket.7 > index f2213eb..5edcb09 100644 > --- a/man7/socket.7 > +++ b/man7/socket.7 > @@ -694,6 +694,31 @@ for details on control messages. > Gets the socket type as an integer (e.g., > .BR SOCK_STREAM ). > This socket option is read-only. > +.TP > +.B SO_BUSY_POLL > +Sets the approximate time in microseconds to busy poll on a blocking receive > +when there is no data. Increasing this value requires > +.BR CAP_NET_ADMIN . > +The default for this option is controlled by the > +.I /proc/sys/net/core/busy_read > +file. > + > +The value in the > +.I /proc/sys/net/core/busy_poll > +file determines how long > +.BR select (2) > +and > +.BR poll (2) > +will busy poll when they operate on sockets with > +.BR SO_BUSY_POLL > +set and no events to report are found. > + > +In both cases busy polling will only be done when the socket last received data > +from a network device that supports this option. > + > +While busy polling may improve latency of some applications, care must be > +taken when using it since this will increase both CPU utilization and power usage. > + > .SS Signals > When writing onto a connection-oriented socket that has been shut down > (by the local or the remote end) > > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
