@@ -277,3 +277,56 @@ mkscott@sacadia.com
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+ From bright@fw.wintelcom.net Tue Jan 2 03:02:28 2001
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+ Received: from fw.wintelcom.net (bright@ns1.wintelcom.net [209.1.153.20])
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+ by candle.pha.pa.us (8.9.0/8.9.0) with ESMTP id DAA16169
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+ for <pgman@candle.pha.pa.us>; Tue, 2 Jan 2001 03:02:27 -0500 (EST)
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+ Received: (from bright@localhost)
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+ by fw.wintelcom.net (8.10.0/8.10.0) id f0282Vm10623;
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+ Tue, 2 Jan 2001 00:02:31 -0800 (PST)
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+ Date: Tue, 2 Jan 2001 00:02:31 -0800
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+ From: Alfred Perlstein <bright@wintelcom.net>
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+ To: Bruce Momjian <pgman@candle.pha.pa.us>
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+ Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
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+ Subject: Re: [HACKERS] Assuming that TAS() will succeed the first time is verboten
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+ Message-ID: <20010102000230.C19572@fw.wintelcom.net>
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+ References: <9850.978067943@sss.pgh.pa.us> <200101020759.CAA15836@candle.pha.pa.us>
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+ Mime-Version: 1.0
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+ Content-Type: text/plain; charset=us-ascii
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+ Content-Disposition: inline
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+ User-Agent: Mutt/1.2.5i
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+ In-Reply-To: <200101020759.CAA15836@candle.pha.pa.us>; from pgman@candle.pha.pa.us on Tue, Jan 02, 2001 at 02:59:20AM -0500
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+ Status: OR
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+
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+ * Bruce Momjian <pgman@candle.pha.pa.us> [010101 23:59] wrote:
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+ > > Alfred Perlstein <bright@wintelcom.net> writes:
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+ > > > One trick that may help is calling sched_yield(2) on a lock miss,
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+ > > > it's a POSIX call and quite new so you'd need a 'configure' test
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+ > > > for it.
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+ > >
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+ > > The author of the current s_lock code seems to have thought that
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+ > > select() with a zero delay would do the equivalent of sched_yield().
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+ > > I'm not sure if that's true on very many kernels, if indeed any...
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+ > >
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+ > > I doubt we could buy much by depending on sched_yield(); if you want
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+ > > to assume POSIX facilities, ISTM you might as well go for user-space
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+ > > semaphores and forget the whole TAS mechanism.
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+ >
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+ >
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+ > Another issue is that sched_yield brings in the pthreads library/hooks
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+ > on some OS's, which we certainly want to avoid.
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+
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+ I know it's a major undertaking, but since the work is sort of done,
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+ have you guys considered the port to solaris threads and seeing about
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+ making a pthreads port of that?
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+
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+ I know it would probably get you considerable gains under Windows
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+ at the expense of dropping some really really legacy system.
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+
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+ Or you could do what apache (is rumored) does and have it do either
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+ threads or processes or both...
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+
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+ --
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+ -Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
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+ "I have the heart of a child; I keep it in a jar on my desk."
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+
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