I was asked to forward this to linux-net. Version 2.4.19 has a problem with network SIGIO. Any attempt to use select() on a network connection results in a continuous stream of signals being received, each showing that "I/O is possible". I'm not on this list....... On Wed, 21 Aug 2002, Richard B. Johnson wrote: > On Wed, 21 Aug 2002, Richard B. Johnson wrote: > > > On Wed, 21 Aug 2002 lists@corewars.org wrote: > > > > > This is a fix included since 2.4.19-pre5-aa1. > > > > > > > Well if this is a 'fix' there is a lot of legacy software that > > just got broken. It was discovered when the new kernel was booted > > on some very reliable file-servers. > > > > > You're assuming that every SIGIO coming your way > > > 1) is coming via fd 0 > > > 2) is a POLL_IN interrupt > > > > > > You should either be polling the file descriptor (0) from the signal > > > handler, or using SA_SIGINFO (see sigaction(2)) to determine > > > which interrupt it is. > > > > > > > I wrote the software to demonstrate the problem, not as an example > > of how to poll the keyboard. > > > > Attached is a script, clearly demonstrating that one cannot > claim that the Linux-2.4.19 SIGIO is functioning properly. > When connected via telnet, a SIGIO is continuously sent to > the connected task, declaring that I/O is possible (of course > I/O is possible...) > > The overhead handling these broken signals makes a network > connection as slow as an RS-232C connection. This cannot be > a correct imterpretation of what SIGIO is supposed to do, > i.e., send a signal every time I/O is possible. > > It used to mean that the I/O status __changed__, usually because > new data were available. The 2.4.19 implementation is broken. > The previous versions since 0.99, worked like other Unixes. > > Cheers, > Dick Johnson > Penguin : Linux version 2.4.19 on an i686 machine (797.90 BogoMips). > The US military has given us many words, FUBAR, SNAFU, now ENRON. > Yes, top management were graduates of West Point and Annapolis. > Cheers, Dick Johnson Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips). The US military has given us many words, FUBAR, SNAFU, now ENRON. Yes, top management were graduates of West Point and Annapolis. - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
