From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <1d73e77a5b74942eb88cb5119949c536@hamnavoe.com>
To: 9fans@9fans.net
From: Richard Miller <9fans@hamnavoe.com>
Date: Sun, 19 Aug 2012 14:37:01 +0100
In-Reply-To: <377d293c5366a0fb65398923b7a6ed38@brasstown.quanstro.net>
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Subject: Re: [9fans] tcp!
Topicbox-Message-UUID: ac443be4-ead7-11e9-9d60-3106f5b1d025

> also i forgot to mention that this version of qread can
> potentially cut the number of reads on tcp channels by up
> to 1/2.  one might as well completely satisfy the read,
> if possible.

This looks like a good idea for tcp.  But there are other
users of qread, with stricter assumptions.  Aren't you in danger
of breaking the contract of pipe(3) which uses qwrite/qread:

          Writes are atomic up to a certain size, typically 32768
          bytes, that is, each write will be delivered in a single
          read by the recipient, provided the receiving buffer is
          large enough.

To preserve the atomicity of qread/qwrite, maybe tcp should be
coalescing the blocks itself by multiple calls to qread.