Date: Tue, 13 Jun 95 12:29:03 MDT From: terry@cs.weber.edu (Terry Lambert) To: wollman@halloran-eldar.lcs.mit.edu (Garrett Wollman) Cc: bde@zeta.org.au, current@FreeBSD.ORG Subject: Re: GENERIC kernel & some basic UNIX pointers Message-ID: <9506131829.AA05399@cs.weber.edu> In-Reply-To: <9506131626.AA01992@halloran-eldar.lcs.mit.edu> from "Garrett Wollman" at Jun 13, 95 12:26:01 pm
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> > The context switches don't stop zmodem from being faster than the kernel ppp > > even when the packet sizes are large. > > Zmodem doesn't have to do any context switches in order to operate. > IIJ-PPP by definition does. Kernel PPP does not. Zmodem is also unidirectional sliding window and doesn't have the normal request/response latency of a TCP connection over PPP. Actually, we are starting more and more to need an async I/O mechanism to cause kernel calls to be non-blocking to avoid context switches and latency as a result of blocking operations. Terry Lambert terry@cs.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.
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