From: Jakub Kicinski <kuba@kernel.org>
To: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Shradha Gupta <shradhagupta@linux.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
Date: Thu, 7 Mar 2024 09:01:45 -0800 [thread overview]
Message-ID: <20240307090145.2fc7aa2e@kernel.org> (raw)
In-Reply-To: <DM6PR21MB14817597567C638DEF020FE3CA202@DM6PR21MB1481.namprd21.prod.outlook.com>
On Thu, 7 Mar 2024 15:49:15 +0000 Haiyang Zhang wrote:
> > > Extend 'ethtool -S' output for mana devices to include per-CPU packet
> > > stats
> >
> > But why? You already have per queue stats.
> Yes. But the q to cpu binding is dynamic, we also want the per-CPU stat
> to analyze the CPU usage by counting the packets and bytes on each CPU.
Dynamic is a bit of an exaggeration, right? On a well-configured system
each CPU should use a single queue assigned thru XPS. And for manual
debug bpftrace should serve the purpose quite well.
Please note that you can't use num_present_cpus() to size stats in
ethtool -S , you have to use possible_cpus(), because the retrieval
of the stats is done in a multi-syscall fashion and there are no
explicit lengths in the API. So you must always report all possible
stats, not just currently active :(
next prev parent reply other threads:[~2024-03-07 17:01 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 14:52 [PATCH] net :mana : Add per-cpu stats for MANA device Shradha Gupta
2024-03-07 15:29 ` Jakub Kicinski
2024-03-07 15:49 ` Haiyang Zhang
2024-03-07 17:01 ` Jakub Kicinski [this message]
2024-03-08 5:30 ` Shradha Gupta
2024-03-08 18:51 ` Haiyang Zhang
2024-03-08 19:22 ` Jakub Kicinski
2024-03-08 19:43 ` Haiyang Zhang
2024-03-08 19:52 ` Rahul Rameshbabu
2024-03-08 20:27 ` Jakub Kicinski
2024-03-08 20:33 ` Sebastian Andrzej Siewior
2024-03-11 4:19 ` Shradha Gupta
2024-03-11 15:49 ` Stephen Hemminger
2024-03-11 15:51 ` Jakub Kicinski
2024-03-11 16:41 ` Stephen Hemminger
2024-03-14 2:57 ` Shradha Gupta
2024-03-14 3:05 ` Stephen Hemminger
2024-03-14 18:27 ` Jakub Kicinski
2024-03-14 18:54 ` Haiyang Zhang
2024-03-14 19:05 ` Jakub Kicinski
2024-03-14 20:01 ` [EXTERNAL] " Alireza Dabagh
2024-04-03 5:43 ` Shradha Gupta
2024-03-07 16:17 ` Haiyang Zhang
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