Received-SPF: pass (google.com: domain of linux-kernel+bounces-102737-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Date: Wed, 13 Mar 2024 20:05:45 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: Shradha Gupta <shradhagupta@linux.microsoft.com>
Cc: Jakub Kicinski <kuba@kernel.org>, Haiyang Zhang
 <haiyangz@microsoft.com>, Shradha Gupta <shradhagupta@microsoft.com>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
 "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
 "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
 "netdev@vger.kernel.org" <netdev@vger.kernel.org>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Ajay Sharma
 <sharmaajay@microsoft.com>, Leon Romanovsky <leon@kernel.org>, Thomas
 Gleixner <tglx@linutronix.de>, Sebastian Andrzej Siewior
 <bigeasy@linutronix.de>, KY Srinivasan <kys@microsoft.com>, Wei Liu
 <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>, Long Li
 <longli@microsoft.com>, Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH] net :mana : Add per-cpu stats for MANA device
Message-ID: <20240313200545.656f6dd6@hermes.local>
In-Reply-To: <20240314025720.GA13853@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
References: <1709823132-22411-1-git-send-email-shradhagupta@linux.microsoft.com>
	<20240307072923.6cc8a2ba@kernel.org>
	<DM6PR21MB14817597567C638DEF020FE3CA202@DM6PR21MB1481.namprd21.prod.outlook.com>
	<20240307090145.2fc7aa2e@kernel.org>
	<CH2PR21MB1480D3ACADFFD2FC3B1BB7ECCA272@CH2PR21MB1480.namprd21.prod.outlook.com>
	<20240308112244.391b3779@kernel.org>
	<20240311041950.GA19647@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
	<20240314025720.GA13853@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit

On Wed, 13 Mar 2024 19:57:20 -0700
Shradha Gupta <shradhagupta@linux.microsoft.com> wrote:

> Following is the data we can share:
> 
> Default interrupts affinity for each queue:
> 
>  25:          1        103          0    2989138  Hyper-V PCIe MSI 4138200989697-edge      mana_q0@pci:7870:00:00.0
>  26:          0          1    4005360          0  Hyper-V PCIe MSI 4138200989698-edge      mana_q1@pci:7870:00:00.0
>  27:          0          0          1    2997584  Hyper-V PCIe MSI 4138200989699-edge      mana_q2@pci:7870:00:00.0
>  28:    3565461          0          0          1  Hyper-V PCIe MSI 4138200989700-edge      mana_q3
> @pci:7870:00:00.0
> 
> As seen the CPU-queue mapping is not 1:1, Queue 0 and Queue 2 are both mapped 
> to cpu3. From this knowledge we can figure out the total RX stats processed by
> each CPU by adding the values of mana_q0 and mana_q2 stats for cpu3. But if
> this data changes dynamically using irqbalance or smp_affinity file edits, the
> above assumption fails. 


irqbalance is often a bad idea.
In the past, doing one shot balancing at startup was a better plan.