Re: [ANNOUNCE] 3.14.64-rt67

[Paul Gortmaker]

On Tue, Mar 15, 2016 at 7:25 PM, Paul Gortmaker
<paul.gortmaker@xxxxxxxxxxxxx> wrote:
> On Tue, Mar 15, 2016 at 5:45 PM, Paul Gortmaker
> <paul.gortmaker@xxxxxxxxxxxxx> wrote:
>> On Mon, Mar 14, 2016 at 11:49 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>>>
>>> Dear RT Folks,
>>>
>>> 3.14 release on PI(E) Day!
>>>
>>> I'm pleased to announce the 3.14.64-rt67 stable release.
>>
>> Testing this with what is largely a x86-64 defconfig but with RT_FULL,
>> I now see:
>>
>> root@dell760-paul:~# dmesg|grep NOH
>> [    8.605854] NOHZ: local_softirq_pending 100
>> [    8.732677] NOHZ: local_softirq_pending 100
>> [    8.852729] NOHZ: local_softirq_pending 100
>> [    8.963964] NOHZ: local_softirq_pending 100
>> [    9.061892] NOHZ: local_softirq_pending 100
>> [    9.184921] NOHZ: local_softirq_pending 100
>> [    9.370958] NOHZ: local_softirq_pending 100
>> [    9.657811] NOHZ: local_softirq_pending 100
>> [    9.942631] NOHZ: local_softirq_pending 100
>> [   10.783710] NOHZ: local_softirq_pending 100
>> root@dell760-paul:~#
>>
>> ...early in boot (we cap them after ~10 msgs).
>>
>> I think 100 is RCU if I did my bit counting properly; remind
>> me to submit a patch that uses the human readable names.
>>
>> I had a good hunch which commit was responsible but I did
>> a check of it and the one directly underneath it to be sure,
>> and the latter boots w/o any pending messages.
>>
>> git log --oneline  v3.14-rt ^v3.14.64
>> [...]
>> 0a80a6849f19 latencyhist: disable jump-labels
>> a884ef48e1ca net: provide a way to delegate processing a softirq to ksoftirqd
>> 780d7ca2fdb0 softirq: split timer softirqs out of ksoftirqd    <------
>> *** fail ***

Oh, and for the record, a884ef directly above relies on 780d7, so one has to
disable both if they want to test the rest of the queue of patches.

Paul.
--

>> 13ad3a61e2c2 preempt-lazy: Add the lazy-preemption check to preempt_schedule()
>> d0bb90f40dbf net: move xmit_recursion to per-task variable on -RT
>> 88f1b110f64d ptrace: don't open IRQs in ptrace_freeze_traced() too early
>> 816f701e4c91 Linux 3.14.61-rt63
>>
>> Have not investigated further yet; going to go test 3.10-rt since in
>> theory it should have the same issue; it has the same commit.
>> If it does, I'll follow up the announce for it with similar details.
>
> So, to summarize 3.10-rt has the issue, 3.14-rt has the issue, but
> 3.18-rt and 4.1-rt do not have the issue.
>
> Hopefully that helps to narrow it down.
>
> Paul.
> --
>
>>
>> Paul.
>> --
>>
>>>
>>>
>>> This release is just an update to the new stable 3.14.64 version
>>> and no RT specific changes have been made.
>>>
>>>
>>> You can get this release via the git tree at:
>>>
>>>   git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git
>>>
>>>   branch: v3.14-rt
>>>   Head SHA1: f1d2391d1c641f19c1e548c6daec89d53093291f
>>>
>>>
>>> Or to build 3.14.64-rt67 directly, the following patches should be applied:
>>>
>>>   http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.14.tar.xz
>>>
>>>   http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.14.64.xz
>>>
>>>   http://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patch-3.14.64-rt67.patch.xz
>>>
>>>
>>>
>>>
>>> Enjoy,
>>>
>>> -- Steve
>>>
>>> --
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