Re: [ANNOUNCE] 3.14.64-rt67

[Paul Gortmaker]

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 ***
> 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
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html