Feedback-ID: id4a34324:Fastmail
Date: Mon, 15 May 2023 17:54:53 -0700
From: Andres Freund <andres@anarazel.de>
To: Michael Paquier <michael@paquier.xyz>
Cc: Alexander Lakhin <exclusion@gmail.com>,
	Michael Paquier <michael.paquier@gmail.com>,
	MARK CALLAGHAN <mdcallag@gmail.com>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: benchmark results comparing versions 15.2 and 16
Message-ID: <20230516005453.wrsldqhhbpy5gfnd@awork3.anarazel.de>
References: <CAFbpF8N4bVFZ+eyWFj_+fZXZFSayk2kJVtZnouUVKGHudiDrSw@mail.gmail.com>
 <b32bed1b-0746-9b20-1472-4bdc9ca66d52@gmail.com>
 <20230508191117.v6475ip6hxpwukss@awork3.anarazel.de>
 <20230509164824.wtfn5aoggj4rcz67@awork3.anarazel.de>
 <ZFxu+IWkQpJhZkB3@paquier.xyz>
 <ZGHBGE45jKW8FEpe@paquier.xyz>
 <20230516001447.xrijuuqcn5s7phuz@awork3.anarazel.de>
 <ZGLRd9RRx/47BrOP@paquier.xyz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZGLRd9RRx/47BrOP@paquier.xyz>
Archived-At: <https://www.postgresql.org/message-id/20230516005453.wrsldqhhbpy5gfnd%40awork3.anarazel.de>
Precedence: bulk

Hi,

On 2023-05-16 09:42:31 +0900, Michael Paquier wrote:
> > I get quite variable performance if I don't pin client / server to the same
> > core, but even the slow performance is faster than 45k.
> 
> Okay.  You mean with something like taskset or similar, I guess?

Yes. numactl --physcpubind ... in my case.  Linux has an optimization where it
does not need to send an IPI when the client and server are scheduled on the
same core. For single threaded ping-pong tasks like pgbench -c1, that can make
a huge difference, particularly on larger CPUs.  So you get a lot better
performance when forcing things to be colocated.

Greetings,

Andres Freund