On Thu, 2011-04-28 at 03:26 -0700, Paul E. McKenney wrote:
> On Thu, Apr 28, 2011 at 11:45:03AM +0200, Sedat Dilek wrote:
> > Hi,
> >
> > not sure if my problem from linux-2.6-rcu.git#sedat.2011.04.23a is
> > related to the issue here.
> >
> > Just FYI:
> > I am here on a Pentium-M (uniprocessor aka UP) and still unsure if I
> > have the correct (optimal?) kernel-configs set.
> >
> > Paul gave me a script to collect RCU data and I enhanced it with
> > collecting SCHED data.
> >
> > In the above mentionned GIT branch I applied these two extra commits
> > (0001 requested by Paul and 0002 proposed by Thomas):
> >
> > patches/0001-Revert-rcu-restrict-TREE_RCU-to-SMP-builds-with-PREE.patch
> > patches/0002-sched-Add-warning-when-RT-throttling-is-activated.patch
> >
> > Furthermore, I have added my kernel-config file, scripts, patches and
> > logs (also output of 'cat /proc/cpuinfo').
> >
> > Hope this helps the experts to narrow down the problem.
>
> Yow!!!
>
> Now this one might well be able to hit the 950 millisecond limit.
> There are no fewer than 1,314,958 RCU callbacks queued up at the end of
> the test. And RCU has indeed noticed this and cranked up the number
> of callbacks to be handled by each invocation of rcu_do_batch() to
> 2,147,483,647. And only 15 seconds earlier, there were zero callbacks
> queued and the rcu_do_batch() limit was at the default of 10 callbacks
> per invocation.
Yeah, yow. Once the RT throttle hit, it stuck.
.clock : 1386824.201768
.rt_nr_running : 2
.rt_throttled : 1
.rt_time : 950.132427
.rt_runtime : 950.000000
rcuc0 7 0.034118 10857 98 0.034118 1472.309646 0.000000 /
FF 1 1 R R 0 [rcuc0]
.clock : 1402450.997994
.rt_nr_running : 2
.rt_throttled : 1
.rt_time : 950.132427
.rt_runtime : 950.000000
rcuc0 7 0.034118 10857 98 0.034118 1472.309646 0.000000 /
FF 1 1 R R 0 [rcuc0]
...
.clock : 2707432.862374
.rt_nr_running : 2
.rt_throttled : 1
.rt_time : 950.132427
.rt_runtime : 950.000000
rcuc0 7 0.034118 10857 98 0.034118 1472.309646 0.000000 /
FF 1 1 R R 0 [rcuc0]
.clock : 2722572.958381
.rt_nr_running : 2
.rt_throttled : 1
.rt_time : 950.132427
.rt_runtime : 950.000000
rcuc0 7 0.034118 10857 98 0.034118 1472.309646 0.000000 /
FF 1 1 R R 0 [rcuc0]
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