From: Tom Lane <tgl@sss.pgh.pa.us>
To: Theo Schlossnagle <jesus@omniti.com>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: josh.berkus@sun.com, robert.lor@sun.com, PostgreSQL-patches <pgsql-patches@postgresql.org>
Subject: Re: [BUGS] BUG #2401: spinlocks not available on amd64
Date: Sat, 29 Apr 2006 15:34:28 -0400
Message-ID: <26185.1146339268@sss.pgh.pa.us> (raw)
In-Reply-To: <445159FA.7070206@omniti.com>
References: <200604272231.k3RMVYM28488@candle.pha.pa.us>
<16483.1146178926@sss.pgh.pa.us>
<445159FA.7070206@omniti.com>
Theo Schlossnagle <jesus@omniti.com> writes:
> I'd remind everyone that the spinlock stuff is entirely optional at
> build time.
Not really. The performance hit for not having hardware spinlocks is
so severe that it's not considered a reasonable fallback.
> I also think it immensely useful to replace all of the tas subsystem
> with cas so that one could reliabily lock these atomics with the process
> id of the locker.
I cannot, ever once in my years working on Postgres, remember having
wanted such a thing. I am strongly against mucking with the spinlock
code for mere aesthetics --- it's too fragile and hard to test,
especially on platforms you don't have ready access to.
In short, it ain't broken and we don't need to fix it.
regards, tom lane
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To: pgsql-patches@postgresql.org
Cc: tgl@sss.pgh.pa.us, jesus@omniti.com, pgman@candle.pha.pa.us
Subject: Re: [BUGS] BUG #2401: spinlocks not available on amd64
In-Reply-To: <26185.1146339268@sss.pgh.pa.us>
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