linux-kernel - Re: [PATCH 1/1] nvme: always enable multipath

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z0DKf0fd5xCmcp5j@kbusch-mbp.dhcp.thefacebook.com>
Date: Fri, 22 Nov 2024 11:16:31 -0700
From: Keith Busch <kbusch@...nel.org>
To: John Meneghini <jmeneghi@...hat.com>
Cc: Christoph Hellwig <hch@....de>, Bryan Gurney <bgurney@...hat.com>,
	linux-kernel@...r.kernel.org, linux-nvme@...ts.infradead.org,
	sagi@...mberg.me, axboe@...nel.dk, mpe@...erman.id.au,
	naveen@...nel.org, maddy@...ux.ibm.com, kernel@...0n.name,
	bmarzins@...hat.com
Subject: Re: [PATCH 1/1] nvme: always enable multipath

On Fri, Nov 22, 2024 at 12:52:51PM -0500, John Meneghini wrote:
> On 11/22/24 10:39, Keith Busch wrote:
> > Anyway, we only use the one physical function, so they're certainly not
> > multipath devices here. We disable the CONFIG option because while the
> > nvme multipath IO overhead is low, it's not zero.
> 
> Do we know what the performance impact is?  Has anybody measured the difference?

It doesn't benefit single path devices, so any cost for it is too high.
It's clearly not free.