Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1434779 > unrolled thread

Re: rcu_preempt self-detected stall on CPU from 4.5-rc3, since 3.17

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: rcu_preempt self-detected stall on CPU from 4.5-rc3, since 3.17 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-06-30 20:00 +0200

#1434779 — Re: rcu_preempt self-detected stall on CPU from 4.5-rc3, since 3.17

On Sat, May 07, 2016 at 08:25:01AM -0700, Paul E. McKenney wrote:
> On Fri, May 06, 2016 at 04:25:16PM +1000, Ross Green wrote:
> > On Sun, Apr 3, 2016 at 6:18 PM, Paul E. McKenney
> > <paulmck@linux.vnet.ibm.com> wrote:

[ . . . ]

> > Thought i would update a few runs with the linux-4.6-rc kernels.
> > 
> > I have attached log outputs through dmesg showing rcu_preempt stall warnings.
> > 
> > 
> > Thought it might be interesting for someone else to look at.
> > 
> > Currently running linux-4.6-rc6 in testing.
> 
> Thank you for sending these, I will look them over!
> 
> Still working to reproduce this quickly enough to do real debug...  :-/

And Peter Zijlstra's patch looks to have hugely reduced the rate of
occurrence of this bug in my testing:

lkml.kernel.org/r/20160523091907.GD15728@worktop.ger.corp.intel.com

Almost all of the issues I am seeing now are transient, do not trigger
RCU CPU stall warnings, and would not have been visible to me before
I upgraded my testing scripts and in-kernel code.  In all the tests I
have run with Peter's fix, I have seen only one run with RCU CPU stall
warnings, and all the stalls in that run were transient, unlike those
that I was seeing before his fix.

I will of course be tracking this stuff down, but the low reproduction
rates will make it slow going.

I am guessing that you no longer see this issue?

							Thanx, Paul

[toc] | [standalone]

Back to top | Article view | linux.kernel

csiph-web