On 02/19/2014 08:50 AM, Josh Boyer wrote:
On Tue, Feb 18, 2014 at 7:03 PM, Prarit Bhargava
<prarit(a)redhat.com> wrote:
>
>
> On 02/18/2014 02:39 PM, Matthew Garrett wrote:
>> On Tue, Feb 18, 2014 at 02:28:55PM -0500, Prarit Bhargava wrote:
>>
>>> The problem is that we've seen users (especially those using clusters)
who do
>>> not want ipmi built in. Their systems generate a tonne of ipmi traffic on
their
>>> systems which they want to ignore. Building IPMI into the kernel results in
>>> situations where processing these messages causes kipmi to climb to 100% for
>>> long periods of time.
>>
>> If the system firmware is sending messages then the default assumption
>> ought to be that it's doing so for a reason.
>
> It is -- it's likely sending health or power information back to the BMC. But
> that's not the issue. Clusters (and others) don't care about the BMC on a
> particular system so they disable IPMI.
Is there an option in the firmware to have it not send those reports?
Unfortunately no.
I realize tweaking firmware options is somewhat of a pain, but if
you're doing your initial cluster setup it seems worthwhile to just
turn it off at the source...
It isn't just clusters -- do a search on "centos kipmi 100%" and you'll
see many
hits from general users who have seen the same thing.
>>> Maybe that can be solved through an 'ipmi=off' option, or maybe off
should be
>>> the default state for handling of these messages?
>>
>> You can disable the various ipmi_si probings via the tryacpi, trydmi and
>> so on options.
>
> That's not intuitive. The current options are awful; one has to specify three
> kernel parameters IIRC. Keep it simple with "ipmi=off", and maybe a /sys
> variable to do it at runtime as well (although ... maybe the ipmi_si module
> parameters are available already?).
There's a number of options already. force_kipmid and
kipmid_max_busy_us seem pretty relevant in addition to the ones
Matthew mentioned.
Or if you want a global off switch, I'm sure upstream would be happy
to take a patch for it with sufficient reasoning.
I can push for that.
>
> I don't get that from the reports I've seen. I think the issue is that there
is
> just a huge volume of traffic on these systems. Googling for "centos kipmi
> 100%" has a lot of hits; we seemingly made a bad choice when we built in IPMI.
> There is a glimmer of hope we can switch back to modular in RHEL.
Has anyone tested something more recent to see if this is still a
problem? Upstream is taking the patch to default to =y, so keeping it
=m in Fedora is possible but it seems like we'd diverge for a use case
that is fairly infrequent for Fedora.
I'll see if I can convince someone to run a test with F20.
P.
josh