From: Keith Busch <kbusch@kernel.org>
To: "Patel, Nirmal" <nirmal.patel@linux.intel.com>
Cc: Xinghui Li <korantwork@gmail.com>,
Jonathan Derrick <jonathan.derrick@linux.dev>,
lpieralisi@kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, Xinghui Li <korantli@tencent.com>
Subject: Re: [PATCH] PCI: vmd: Do not disable MSI-X remapping in VMD 28C0 controller
Date: Thu, 9 Feb 2023 16:05:31 -0700 [thread overview]
Message-ID: <Y+V8O9kDH5ZXWdBF@kbusch-mbp.dhcp.thefacebook.com> (raw)
In-Reply-To: <c830a68e-014b-ddec-4bab-5db337fc378f@linux.intel.com>
On Tue, Feb 07, 2023 at 01:32:20PM -0700, Patel, Nirmal wrote:
> On 2/6/2023 8:18 PM, Xinghui Li wrote:
> > Keith Busch <kbusch@kernel.org> 于2023年2月7日周二 02:28写道：
> >> I suspect bypass is the better choice if "num_active_cpus() > pci_msix_vec_count(vmd->dev)".
> > For this situation, My speculation is that the PCIE nodes are
> > over-mounted and not just because of the CPU to Drive ratio.
> > We considered designing online nodes, because we were concerned that
> > the IO of different chunk sizes would adapt to different MSI-X modes.
> > I privately think that it may be logically complicated if programmatic
> > judgments are made.
>
> Also newer CPUs have more MSIx (128) which means we can still have
> better performance without bypass. It would be better if user have
> can chose module parameter based on their requirements. Thanks.
So what? More vectors just pushes the threshold to when bypass becomes
relevant, which is exactly why I suggested it. There has to be an empirical
answer to when bypass beats muxing. Why do you want a user tunable if there's a
verifiable and automated better choice?
next prev parent reply other threads:[~2023-02-09 23:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-22 7:26 [PATCH] PCI: vmd: Do not disable MSI-X remapping in VMD 28C0 controller korantwork
2022-12-22 9:15 ` Jonathan Derrick
2022-12-22 21:56 ` Keith Busch
2022-12-23 8:02 ` Xinghui Li
2022-12-27 22:32 ` Jonathan Derrick
2022-12-28 2:19 ` Xinghui Li
2023-01-09 21:00 ` Jonathan Derrick
2023-01-10 12:28 ` Xinghui Li
2023-02-06 12:45 ` Xinghui Li
2023-02-06 18:11 ` Patel, Nirmal
2023-02-06 18:28 ` Keith Busch
2023-02-07 3:18 ` Xinghui Li
2023-02-07 20:32 ` Patel, Nirmal
2023-02-09 12:05 ` Xinghui Li
2023-02-09 23:05 ` Keith Busch [this message]
2023-02-09 23:57 ` Patel, Nirmal
2023-02-10 0:47 ` Keith Busch
2022-12-23 7:53 ` Xinghui Li
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y+V8O9kDH5ZXWdBF@kbusch-mbp.dhcp.thefacebook.com \
--to=kbusch@kernel.org \
--cc=jonathan.derrick@linux.dev \
--cc=korantli@tencent.com \
--cc=korantwork@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=nirmal.patel@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox