netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Saeed Mahameed <saeedm@mellanox.com>
To: "sashal@kernel.org" <sashal@kernel.org>
Cc: "ecree@solarflare.com" <ecree@solarflare.com>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"gerlitz.or@gmail.com" <gerlitz.or@gmail.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"kuba@kernel.org" <kuba@kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"leon@kernel.org" <leon@kernel.org>
Subject: Re: [PATCH AUTOSEL 4.9 09/26] net/mlx5e: Init ethtool steering for representors
Date: Thu, 16 Apr 2020 21:08:06 +0000	[thread overview]
Message-ID: <3226e1df60666c0c4e3256ec069fee2d814d9a03.camel@mellanox.com> (raw)
In-Reply-To: <20200416195859.GP1068@sasha-vm>

On Thu, 2020-04-16 at 15:58 -0400, Sasha Levin wrote:
> On Thu, Apr 16, 2020 at 07:07:13PM +0000, Saeed Mahameed wrote:
> > On Thu, 2020-04-16 at 09:30 -0400, Sasha Levin wrote:
> > > On Thu, Apr 16, 2020 at 08:24:09AM +0300, Leon Romanovsky wrote:
> > > > On Thu, Apr 16, 2020 at 04:08:10AM +0000, Saeed Mahameed wrote:
> > > > > On Wed, 2020-04-15 at 20:00 -0400, Sasha Levin wrote:
> > > > > > On Wed, Apr 15, 2020 at 05:18:38PM +0100, Edward Cree
> > > > > > wrote:
> > > > > > > Firstly, let me apologise: my previous email was too
> > > > > > > harsh
> > > > > > > and too
> > > > > > >  assertiveabout things that were really more uncertain
> > > > > > > and
> > > > > > > unclear.
> > > > > > > 
> > > > > > > On 14/04/2020 21:57, Sasha Levin wrote:
> > > > > > > > I've pointed out that almost 50% of commits tagged for
> > > > > > > > stable do
> > > > > > > > not
> > > > > > > > have a fixes tag, and yet they are fixes. You really
> > > > > > > > deduce
> > > > > > > > things based
> > > > > > > > on coin flip probability?
> > > > > > > Yes, but far less than 50% of commits *not* tagged for
> > > > > > > stable
> > > > > > > have
> > > > > > > a fixes
> > > > > > >  tag.  It's not about hard-and-fast Aristotelian
> > > > > > > "deductions", like
> > > > > > > "this
> > > > > > >  doesn't have Fixes:, therefore it is not a stable
> > > > > > > candidate", it's
> > > > > > > about
> > > > > > >  probabilistic "induction".
> > > > > > > 
> > > > > > > > "it does increase the amount of countervailing evidence
> > > > > > > > needed to
> > > > > > > > conclude a commit is a fix" - Please explain this
> > > > > > > > argument
> > > > > > > > given
> > > > > > > > the
> > > > > > > > above.
> > > > > > > Are you familiar with Bayesian statistics?  If not, I'd
> > > > > > > suggest
> > > > > > > reading
> > > > > > >  something like http://yudkowsky.net/rational/bayes/
> > > > > > > which
> > > > > > > explains
> > > > > > > it.
> > > > > > > There's a big difference between a coin flip and a
> > > > > > > _correlated_
> > > > > > > coin flip.
> > > > > > 
> > > > > > I'd maybe point out that the selection process is based on
> > > > > > a
> > > > > > neural
> > > > > > network which knows about the existence of a Fixes tag in a
> > > > > > commit.
> > > > > > 
> > > > > > It does exactly what you're describing, but also taking a
> > > > > > bunch
> > > > > > more
> > > > > > factors into it's desicion process ("panic"? "oops"?
> > > > > > "overflow"?
> > > > > > etc).
> > > > > > 
> > > > > 
> > > > > I am not against AUTOSEL in general, as long as the decision
> > > > > to
> > > > > know
> > > > > how far back it is allowed to take a patch is made
> > > > > deterministically
> > > > > and not statistically based on some AI hunch.
> > > > > 
> > > > > Any auto selection for a patch without a Fixes tags can be
> > > > > catastrophic
> > > > > .. imagine a patch without a Fixes Tag with a single line
> > > > > that is
> > > > > fixing some "oops", such patch can be easily applied cleanly
> > > > > to
> > > > > stable-
> > > > > v.x and stable-v.y .. while it fixes the issue on v.x it
> > > > > might
> > > > > have
> > > > > catastrophic results on v.y ..
> > > > 
> > > > I tried to imagine such flow and failed to do so. Are you
> > > > talking
> > > > about
> > > > anything specific or imaginary case?
> > > 
> > > It happens, rarely, but it does. However, all the cases I can
> > > think
> > > of
> > > happened with a stable tagged commit without a fixes where it's
> > > backport
> > > to an older tree caused unintended behavior (local denial of
> > > service
> > > in
> > > one case).
> > > 
> > > The scenario you have in mind is true for both stable and non-
> > > stable
> > > tagged patches, so it you want to restrict how we deal with
> > > commits
> > > that
> > > don't have a fixes tag shouldn't it be true for *all* commits?
> > 
> > All commits? even the ones without "oops" in them ? where does this
> > stop ? :)
> > We _must_ have a hard and deterministic cut for how far back to
> > take a
> > patch based on a human decision.. unless we are 100% positive
> > autoselection AI can never make a mistake.
> > 
> > Humans are allowed to make mistakes, AI is not.
> 
> Oh I'm reviewing all patches myself after the bot does it's
> selection,
> you can blame me for these screw ups.
> 
> > If a Fixes tag is wrong, then a human will be blamed, and that is
> > perfectly fine, but if we have some statistical model that we know
> > it
> > is going to be wrong 0.001% of the time.. and we still let it run..
> > then something needs to be done about this.
> > 
> > I know there are benefits to autosel, but overtime, if this is not
> > being audited, many pieces of the kernel will get broken unnoticed
> > until some poor distro decides to upgrade their kernel version.
> 
> Quite a few distros are always running on the latest LTS releases,
> Android isn't that far behind either at this point.
> 
> There are actually very few non-LTS users at this point...
> 
> > > > <...>
> > > > > > Let me put my Microsoft employee hat on here. We have
> > > > > > driver/net/hyperv/
> > > > > > which definitely wasn't getting all the fixes it should
> > > > > > have
> > > > > > been
> > > > > > getting without AUTOSEL.
> > > > > > 
> > > > > 
> > > > > until some patch which shouldn't get backported slips
> > > > > through,
> > > > > believe
> > > > > me this will happen, just give it some time ..
> > > > 
> > > > Bugs are inevitable, I don't see many differences between bugs
> > > > introduced by manually cherry-picking or automatically one.
> > > 
> > > Oh bugs slip in, that's why I track how many bugs slipped via
> > > stable
> > > tagged commits vs non-stable tagged ones, and the statistic may
> > > surprise
> > > you.
> > > 
> > 
> > Statistics do not matter here, what really matters is that there is
> > a
> > possibility of a non-human induced error, this should be a no no.
> > or at least make it an opt-in thing for those who want to take
> > their
> > chances and keep a close eye on it..
> 
> Hrm, why? Pretend that the bot is a human sitting somewhere sending
> mails out, how does it change anything?
> 

If i know a bot might do something wrong, i Fix it and make sure it
will never do it again. For humans i just can't do that, can I ? :)
so this is the difference and why we all have jobs .. 

> > > The solution here is to beef up your testing infrastructure
> > > rather
> > > than
> > 
> > So please let me opt-in until I beef up my testing infra.
> 
> Already did :)

No you didn't :), I received more than 5 AUTOSEL emails only today and
yesterday.

Please don't opt mlx5 out just yet ;-), i need to do some more research
and make up my mind..

> 
> > > taking less patches; we still want to have *all* the fixes,
> > > right?
> > > 
> > 
> > if you can be sure 100% it is the right thing to do, then yes,
> > please
> > don't hesitate to take that patch, even without asking anyone !!
> > 
> > Again, Humans are allowed to make mistakes.. AI is not.
> 
> Again, why?
> 

Because AI is not there yet.. and this is a very big philosophical
question.

Let me simplify: there is a bug in the AI, where it can choose a wrong
patch, let's fix it.





  reply	other threads:[~2020-04-16 21:08 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-11 23:13 [PATCH AUTOSEL 4.9 01/26] net: wan: wanxl: use allow to pass CROSS_COMPILE_M68k for rebuilding firmware Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 02/26] net: phy: probe PHY drivers synchronously Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 04/26] net: phy: mscc: accept all RGMII species in vsc85xx_mac_if_set Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 06/26] mwifiex: set needed_headroom, not hard_header_len Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 07/26] Bluetooth: L2CAP: handle l2cap config request during open state Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 09/26] net/mlx5e: Init ethtool steering for representors Sasha Levin
2020-04-12  7:10   ` Or Gerlitz
2020-04-12 17:59     ` Jakub Kicinski
2020-04-12 18:29       ` Or Gerlitz
2020-04-14  1:56       ` Sasha Levin
2020-04-14  7:16         ` Leon Romanovsky
2020-04-14 10:22         ` Or Gerlitz
2020-04-14 11:09           ` Greg KH
2020-04-14 14:38             ` Or Gerlitz
2020-04-14 15:16               ` Sasha Levin
2020-04-14 15:49               ` Edward Cree
2020-04-14 17:37                 ` Leon Romanovsky
2020-04-14 19:03                   ` Jakub Kicinski
2020-04-14 21:00                   ` Sasha Levin
2020-04-14 22:50                   ` Michal Kubecek
2020-04-15  5:31                     ` Leon Romanovsky
2020-04-15 14:07                     ` Sasha Levin
2020-04-14 20:57                 ` Sasha Levin
2020-04-15 16:18                   ` Edward Cree
2020-04-16  0:00                     ` Sasha Levin
2020-04-16  4:08                       ` Saeed Mahameed
2020-04-16  5:24                         ` Leon Romanovsky
2020-04-16 13:30                           ` Sasha Levin
2020-04-16 19:07                             ` Saeed Mahameed
2020-04-16 19:58                               ` Sasha Levin
2020-04-16 21:08                                 ` Saeed Mahameed [this message]
2020-04-17  8:28                                   ` gregkh
2020-04-17 22:23                                     ` Saeed Mahameed
2020-04-18 10:51                                       ` gregkh
2020-04-17 13:21                                   ` Sasha Levin
2020-04-17 22:38                                     ` Saeed Mahameed
2020-04-16 13:40                       ` Or Gerlitz
2020-04-16 14:04                         ` Sasha Levin
2020-04-16 14:17                           ` Or Gerlitz
2020-04-16 14:36                             ` Sasha Levin
2020-04-16 17:20                         ` Greg KH
2020-04-16 19:31                           ` Saeed Mahameed
2020-04-16 19:53                             ` Sasha Levin
2020-04-16 21:32                               ` Saeed Mahameed
2020-04-16 23:23                                 ` Sasha Levin
2020-04-21  3:07                                   ` Saeed Mahameed
2020-04-16 20:08                             ` Jakub Kicinski
2020-04-16 21:11                               ` Saeed Mahameed
2020-04-17  8:25                                 ` gregkh
2020-04-16 16:06                       ` Edward Cree
2020-04-16 18:49                         ` Sasha Levin
2020-04-20 11:45                           ` Edward Cree
2020-04-20 12:53                             ` Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 10/26] Bluetooth: Fix calculation of SCO handle for packet processing Sasha Levin
2020-04-11 23:13 ` [PATCH AUTOSEL 4.9 11/26] Bluetooth: guard against controllers sending zero'd events Sasha Levin
2020-04-11 23:14 ` [PATCH AUTOSEL 4.9 13/26] net: intel: e1000e: fix possible sleep-in-atomic-context bugs in e1000e_get_hw_semaphore() Sasha Levin
2020-04-11 23:14 ` [PATCH AUTOSEL 4.9 19/26] Bluetooth: RFCOMM: fix ODEBUG bug in rfcomm_dev_ioctl Sasha Levin
2020-04-11 23:14 ` [PATCH AUTOSEL 4.9 20/26] brcmfmac: Fix driver crash on USB control transfer timeout Sasha Levin
2020-04-11 23:14 ` [PATCH AUTOSEL 4.9 26/26] svcrdma: Fix leak of transport addresses Sasha Levin

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=3226e1df60666c0c4e3256ec069fee2d814d9a03.camel@mellanox.com \
    --to=saeedm@mellanox.com \
    --cc=davem@davemloft.net \
    --cc=ecree@solarflare.com \
    --cc=gerlitz.or@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=kuba@kernel.org \
    --cc=leon@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=sashal@kernel.org \
    --cc=stable@vger.kernel.org \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
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).