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Date: Fri, 8 Jun 2007 02:46:19 +0800
From: Samuel Thibault <samuel DOT thibault AT ens-lyon DOT org>
To: cygwin AT cygwin DOT com
Subject: Re: [ANNOUNCEMENT] New package: brltty 3.8
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Lev Bishop, le Thu 07 Jun 2007 14:39:17 -0400, a écrit :
> On 6/7/07, Samuel Thibault wrote:
> >Lev Bishop, le Thu 07 Jun 2007 13:41:44 -0400, a écrit :
> >> ...around 80MByte/sec, which maybe isn't as fast as it could be using
> >> native functionality, but surely brltty doesn't need *that* much
> >> bandwidth for transferring text?
> >
> >It doesn't need bandwidth, it needs latency.
> 
> Latency is...
> bash-3.2$ ./socat TCP-LISTEN:5001 PIPE & exec
> 99<>/dev/tcp/127.0.0.1/5001 ; time for (( a=0; a<1000; a++ )); do echo
> $a >&99; read <&99; done; exec 99>&-
> [1] 4492
> 
> real    0m1.959s
> user    0m0.062s
> sys     0m0.172s
> bash-3.2$
> [1]+  Done                    ./socat TCP-LISTEN:5001 PIPE
> 
> ...about 2ms round-trip. How is this a problem?

This adds up to the screen reader latency, etc.

Really, we tried both, and while tcp/ip was a bit painful, local sockets
were smooth.

Samuel

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