From: Haojun Bao <baohaojun@gmail.com>
To: cygwin@cygwin.com
Subject: Re: How cygwin realize posix pipe?
In-Reply-To: <20090730104914.52236.qmail@web3314.mail.ogk.yahoo.co.jp> 	(Tatsuro MATSUOKA's message of "Thu, 30 Jul 2009 19:49:14 +0900 	(JST)")
References: <20090730104914.52236.qmail@web3314.mail.ogk.yahoo.co.jp>
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Date: Thu, 30 Jul 2009 21:45:39 +0800
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Tatsuro MATSUOKA <tmacchant2@yahoo.co.jp> writes:

> Hello
>
> I have involved in the octave project.
> Octave uses gnuplot as a graphic backend and data are sent and recieved via pipe.
>
> A report of slowness issue of the plot on octave on windows reported.

So one of your program is native and the other cygwin.

It's like a similar issue I met when using native Emacs+Gnus and cygwin
programs (openssl client) to read imap mails, it is very slow.

I guess it was a pipe size issue, for old DOS compatibility, the pipe
buffer is 64K, and if I check the i/o rate of openssl with Procexp, I
can see something like 64K.

This is a very wild guess though. First I see sth. in Procexp to be
about 64K, then I googled with "windows pipe 64k". Maybe you can try
tweak the pipe buffer size.

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