LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Dexuan Cui <decui@microsoft.com>
To: Haiyang Zhang <haiyangz@microsoft.com>,
	"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: KY Srinivasan <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Paul Rosswurm <paulros@microsoft.com>,
	Shachar Raindel <shacharr@microsoft.com>,
	"olaf@aepfle.de" <olaf@aepfle.de>, vkuznets <vkuznets@redhat.com>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net-next] mana: Add support for EQ sharing
Date: Tue, 24 Aug 2021 01:38:44 +0000	[thread overview]
Message-ID: <BYAPR21MB1270B8B3B70465B7B355EF86BFC59@BYAPR21MB1270.namprd21.prod.outlook.com> (raw)
In-Reply-To: <MN2PR21MB1295573318B3897A2039B094CAC29@MN2PR21MB1295.namprd21.prod.outlook.com>

> From: Haiyang Zhang <haiyangz@microsoft.com>
> Sent: Saturday, August 21, 2021 2:18 PM
> To: Dexuan Cui <decui@microsoft.com>; linux-hyperv@vger.kernel.org;
> >
> > 4) support up to 64 queues per net interface (it was 16). It looks like
> > the default number of queues is also 64 if the VM has >=64 CPUs? --
> > should we add a new field apc->default_queues and limit it to 16 or 32?
> > We'd like to make sure typically the best performance can be achieved
> > with the default number of queues.
> I found on a 40 cpu VM, the mana_query_vport_cfg() returns max_txq:32,
> max_rxq:32, so I didn't further reduce the number (32) from PF.
> 
> That's also the opinion from the host team -- if they upgrade the NIC
> HW in the future, they can adjust the setting from PF side without
> requiring VF driver change.

Ah, I forgot this. Thanks for the explanation!  

> > 5) If the VM has >=64 CPUs, with the patch we create 1 HWC EQ and 64 NIC
> > EQs, and IMO the creation of the last NIC EQ fails since now the host PF
> > driver allows only 64 MSI-X interrupts? If this is the case, I think
> > mana_probe() -> mana_create_eq() fails and no net interface will be
> > created. It looks like we should create up to 63 NIC EQs in this case,
> > and make sure we don't create too many SQs/RQs accordingly.
> >
> > At the end of mana_gd_query_max_resources(), should we add something
> > like:
> > 	if (gc->max_num_queues >= gc->num_msix_usable -1)
> > 		gc->max_num_queues = gc->num_msix_usable -1;
> As said, the PF allows 32 queues, and 64 MSI-X interrupts for now.
> The PF should increase the MSI-X limit if the #queues is increased to
> 64+.

Makes sense. My description was a false alarm.
 
> But for robustness, I like your idea that add a check in VF like above.

Thanks!


      reply	other threads:[~2021-08-24  1:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20 20:42 Haiyang Zhang
2021-08-21  0:32 ` Dexuan Cui
2021-08-21 21:17   ` Haiyang Zhang
2021-08-24  1:38     ` Dexuan Cui [this message]

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=BYAPR21MB1270B8B3B70465B7B355EF86BFC59@BYAPR21MB1270.namprd21.prod.outlook.com \
    --to=decui@microsoft.com \
    --cc=davem@davemloft.net \
    --cc=haiyangz@microsoft.com \
    --cc=kys@microsoft.com \
    --cc=linux-hyperv@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=olaf@aepfle.de \
    --cc=paulros@microsoft.com \
    --cc=shacharr@microsoft.com \
    --cc=sthemmin@microsoft.com \
    --cc=vkuznets@redhat.com \
    --subject='RE: [PATCH net-next] mana: Add support for EQ sharing' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).