From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Tue, 22 Mar 2005 14:40:17 -1000
From: Tim Newsham <newsham@lava.net>
To: Sergey Reva <rs_rlab@mail.ru>,
	Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] How it work?
In-Reply-To: <16725440859.20050322210023@mail.ru>
Message-ID: <Pine.BSI.4.61.0503221431500.25349@malasada.lava.net>
References: <16725440859.20050322210023@mail.ru>
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> I try understand synchronization in Plan 9.
> I find test-and-set routines (for PC) in l.s, but I can't find where
> it used. Also I can't find any reason why it unused... so where it used?

The kernel's files are spread out over /sys/src/9/{pc,port,ip}.
Take a look at port/{qlock,taslock}.c.

> And why rendezvous is syscall, but lock, qlock are library routines
> which look like the same as kernel qlock.c

There are several types of locks.  Some (like spin locks) can operate
without any assistance from the kernel (not entirely, they yield with a
syscall).  Others (like rendezvous) use the kernel to mediate between the
processes. The lock(2) man page has more details.

Tim N.