Date: 20 Oct 1998 15:27:00 -0500 From: sfarrell@farrell.org To: freebsd questions <questions@FreeBSD.ORG> Subject: sio overflows on toshiba 500CDT Message-ID: <87hfwzou7f.fsf@couatl.uchicago.edu>
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I have a toshiba 500CDT with an August 13 2.2-stable system. I am using the internal modem on this unit for PPP access. I am using the ijppp user-mode ppp package. The problem I'm having is the following: certain network programs, most notably emacs and netscape, seem to "stall" quite frequently and in repeatable ways. For example, whenever I try to use completion with emacs, it will appear to lock up (C-g doesn't work; nothing works) for an extended period of time (minutes). However, while this is occuring, I can freely use another telnet session! (I connect to emacs using gnuclient and screen, so when this happens I kill my connection and try again, until I can do what I want.) The link is still up and responsive, it's just the application that seems to be halting. Similarly, some web pages start to load but will not finish, or will "stall" for 2-10 minutes before finishing downloading. This behavior is highly repeatable. Recently I noticed that when this behavior occurs, that I get *many* sio overflows. I'm used to sio overflows occurring with dial-up connections, so usually I ignore these. However, in these cases I've noticed that sio overflows go up to 200/sec, and their rate seems to be directly related the the frustrating behavior. Other applications, notably large ftp transfers, show no unusual behavior at all. I've encountered this behavior with ctsrts enabled and disabled. The serial port is set to 115200. [My analysis of this problem, fwiw, is that ftp transfers are pre-compressed files, and thus tend to stream in to the serial port at a constant rate. However, HTML, e.g., is not compressed so the modem does more internal compression, and inflates the speed with which it accesses the serial port, thus causing the overflows. Then overflows lead to excessive dropped packages, which seems to throw that application's tcp connection off-kilter, even though others might have no problem at all.] Thanks in advance for assistance! -- Steve Farrell To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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