On Thu, Apr 21, 2011 at 04:47:31PM +0200, Sedat Dilek wrote: > On Thu, Apr 21, 2011 at 4:28 PM, Paul E. McKenney > <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > > On Thu, Apr 21, 2011 at 02:49:37PM +0200, Sedat Dilek wrote: > >> On Thu, Apr 21, 2011 at 12:24 PM, Sedat Dilek > >> <sedat.dilek@xxxxxxxxxxxxxx> wrote: [ . . . ] > >> Here the results from the 2nd-run (PREEMPT_RCU enabled). > > > > OK, and the grace periods clearly stopped advancing early on. > > > > Beyond that point, the per-CPU kthread is blocked, but RCU has some > > work for it to do. So someone has called invoke_rcu_cpu_kthread(), > > but rcu_cpu_kthread() is still blocked. I don't see a bug right > > off-hand, but it is early in the morning for me, so I might easily > > be missing something. > > > > Hmmm... > > > > The synchronization between these two assumes that the per-CPU > > kthread is always bound to the respective CPU, so if was somehow > > being migrated off, that might explain these results. > > > > I will add some more diagnostics, test them locally, then push > > out an update. Seem reasonable? > > > > And thank you again for the testing!!! > > Ping me when you have new stuff for testing. > Tomorrow (friday), here is public holiday and monday, too. > So a looong weekend. ;-) OK, I have a new sedat.2011.04.21a branch in the -rcu git tree: git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu.git This is against 2.6.39-rc3, as before. (Yes, I do need to rebase to 2.6.39-rc4, but didn't want to change any more than I had to.) I also have an updated script, which is attached. The output is similar to the earlier one, and it operated is pretty much the same way. Have a great weekend, and I look forward to seeing what shows up on this round. I confess to still being quite puzzled! Thanx, Paul
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