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From: Saeed Mahameed <saeedm@dev.mellanox.co.il>
To: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Linux Netdev List <netdev@vger.kernel.org>,
	Tariq Toukan <tariqt@mellanox.com>
Subject: Re: [PATCH] mlx4: give precise rx/tx bytes/packets counters
Date: Mon, 28 Nov 2016 23:55:25 +0200	[thread overview]
Message-ID: <CALzJLG8qjz7Qx8rWbthtJ1uJt2c8w_1gMeRkmB+SZ+xv2Eu3EQ@mail.gmail.com> (raw)
In-Reply-To: <20161128.154057.1355209532933900181.davem@davemloft.net>

On Mon, Nov 28, 2016 at 10:40 PM, David Miller <davem@davemloft.net> wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Sat, 26 Nov 2016 18:16:00 -0800
>
>> On Sun, 2016-11-27 at 00:47 +0200, Saeed Mahameed wrote:
>>> On Fri, Nov 25, 2016 at 5:46 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>>
>>> As you see here in SRIOV mode (PF only) reads   sw stats from FW.
>>> Tariq, I think we need to fix this.
>>
>> Sure, my patch does not change this at all.
>>
>> If mlx4_is_master() is false, then we aggregate the software states and
>> only the software stats.
>>
>> My patch makes this aggregation possible at the time ethtool or
>> ndo_get_stat64() are called, since this absolutely not depend on the 250
>> ms timer fetching hardware stats.
>
> Saeed please provide counter arguments or ACK this patch, thank you.

I have nothing against this patch, I just wanted to point out that
this patch is just fixing the symptom.
We keep ignoring the root cause that dev_get_stats is called under a
spin_lock which really ties our hands "us device drivers developers"
and push us towards those fragile solutions like deferred work for
caching statistics.
I am not saying that Eric should fix this in his patch, i just wanted
to raise the awareness of the root cause.

Regarding the SRIOV PF stats, i will take it with Tariq internally.

Bottom line, I ACK this patch, I might even do the same myself for
mlx5 :), but there are some follow ups that need to be done.

  reply	other threads:[~2016-11-28 21:55 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-25 15:46 [PATCH] mlx4: give precise rx/tx bytes/packets counters Eric Dumazet
2016-11-25 16:03 ` David Laight
2016-11-25 16:16   ` Eric Dumazet
2016-11-25 16:30     ` Aw: " Lino Sanfilippo
2016-11-25 19:19       ` Eric Dumazet
2016-11-28 22:02         ` Lino Sanfilippo
2016-11-29  0:19           ` Eric Dumazet
2016-11-30 15:28             ` David Laight
2016-11-30 15:47               ` Eric Dumazet
2016-11-26 22:47 ` Saeed Mahameed
2016-11-27  2:16   ` Eric Dumazet
2016-11-28 20:40     ` David Miller
2016-11-28 21:55       ` Saeed Mahameed [this message]
2016-11-28 22:57         ` Eric Dumazet
2016-11-29 18:37 ` David Miller
2016-11-30 14:08 ` Regression: " Jesper Dangaard Brouer
2016-11-30 15:58   ` Eric Dumazet
2016-11-30 16:46     ` Saeed Mahameed
2016-11-30 17:35       ` Eric Dumazet
2016-11-30 20:42         ` Saeed Mahameed
2016-11-30 21:00           ` Eric Dumazet
2016-12-01 12:37             ` Jesper Dangaard Brouer
2016-12-01 13:02               ` [PATCH net-next] mlx4: fix use-after-free in mlx4_en_fold_software_stats() Eric Dumazet
2016-12-01 15:23                 ` Saeed Mahameed
2016-12-02 18:36                 ` David Miller
2016-12-01 15:38             ` Regression: [PATCH] mlx4: give precise rx/tx bytes/packets counters Saeed Mahameed
2016-12-01 15:55               ` Eric Dumazet
2016-12-01 16:08                 ` Eric Dumazet
2016-12-01 17:36                   ` Eric Dumazet
2016-12-04 13:23                     ` Saeed Mahameed
2016-12-01 16:33                 ` Saeed Mahameed
2016-12-01 17:08                   ` Eric Dumazet
2016-12-04 13:21                     ` Saeed Mahameed

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