From: Robert Haas <robertmhaas@gmail.com>
To: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Should we cacheline align PGXACT?
Date: Sat, 20 Aug 2016 14:33:13 -0400
Message-ID: <7503E425-6651-4D40-83FD-592AF580D618@gmail.com> (raw)
In-Reply-To: <CAPpHfdtJY4zOEDsjad6J5AyZMqZcv6gSY9AkKpA7qN3jyQ2+1Q@mail.gmail.com>
References: <CAPpHfdtJY4zOEDsjad6J5AyZMqZcv6gSY9AkKpA7qN3jyQ2+1Q@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>
On Aug 19, 2016, at 2:12 AM, Alexander Korotkov <a.korotkov@postgrespro.ru> wrote:
> Hackers,
>
> originally this idea was proposed by Andres Freund while experimenting with lockfree Pin/UnpinBuffer [1].
> The patch is attached as well as results of pgbench -S on 72-cores machine. As before it shows huge benefit in this case.
> For sure, we should validate that it doesn't cause performance regression in other cases. At least we should test read-write and smaller machines.
> Any other ideas?
Wow, nice results. My intuition on why PGXACT helped in the first place was that it minimized the number of cache lines that had to be touched to take a snapshot. Padding obviously would somewhat increase that again, so I can't quite understand why it seems to be helping... any idea?
...Robert
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: robertmhaas@gmail.com, a.korotkov@postgrespro.ru
Subject: Re: Should we cacheline align PGXACT?
In-Reply-To: <7503E425-6651-4D40-83FD-592AF580D618@gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox