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!
prev parent 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 [PATCH net-next] mana: Add support for EQ sharing 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]
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