Re: Latches with weak memory ordering (Re: max_wal_senders must die)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Markus Wanner <markus(at)bluegap(dot)ch>
Cc: Aidan Van Dyk <aidan(at)highrise(dot)ca>, Andres Freund <andres(at)anarazel(dot)de>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Josh Berkus <josh(at)agliodbs(dot)com>
Subject: Re: Latches with weak memory ordering (Re: max_wal_senders must die)
Date: 2010-11-19 15:51:00
Message-ID: 155.1290181860@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Markus Wanner <markus(at)bluegap(dot)ch> writes:
> Well, that certainly doesn't apply to full fences, that are not specific
> to a particular piece of memory. I'm thinking of 'mfence' on x86_64 or
> 'mf' on ia64.

Hm, what do those do exactly? We've never had any such thing in the
Intel-ish spinlock asm, but if out-of-order writes are possible I should
think we'd need 'em. Or does "lock xchgb" imply an mfence?

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2010-11-19 15:58:03 Re: duplicate connection failure messages
Previous Message Pavel Stehule 2010-11-19 15:49:07 Re: final patch - plpgsql: for-in-array