Re: Any idea about what makes Emacs slow reading on pipes?

[Andreas Schwab <schwab@suse.de>]

David.Kastrup@t-online.de (David Kastrup) writes:

|> "Jan D." <jan.h.d@swipnet.se> writes:
|> 
|> > >
|> > > The following exhibits abysmal speed within Emacs:
|> > >
|> > > (let (process-connection-type) (switch-to-buffer (generate-new-buffer
|> > > "*test*"))(erase-buffer)(start-process "test" (current-buffer) "sh"
|> > > "-c" "hexdump -v /dev/zero|dd bs=1 count=100k")(erase-buffer))
|> > 
|> > ...
|> > 
|> > > The system I see this in is
|> > > GNU Emacs 21.3.50.3 (i686-pc-linux-gnu)
|> > > a RedHat 9 system, but I have seen this in practically every Linux
|> > > system up to now.  Is this a Linux-specific problem, or do others see
|> > > this as well?
|> > 
|> > I could not reproduce this on a slackware (version unknown, but libc 6)
|> > or a Mandrake 9.0 system.  Maybe running under strace can give some
|> > indication of the system call that takes time (if that is the issue)?
|> 
|> Here is a more elaborate test file

Tried on ppc-suse-linux, I get constant throughput of 1024 characters at a
time.  On MacOS X (through MOL) I get varying packet sizes between 97 and
1024.

Andreas.

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Andreas Schwab, SuSE Labs, schwab@suse.de
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