Hi guys, On Fri, May 30, 2014 at 08:08:38PM +0100, Kevin Hilman wrote: > Will Deacon <will.dea...@arm.com> writes: > > I'd like to give these some stress testing before it gets merged, so I'm > > not sure if it'll make it for 3.16 given where we are at the moment. > > FWIW, this feature is disabled by default. I use the following kconfig > fragment to enable the various parts I use for testing: > > CONFIG_NO_HZ=y > CONFIG_NO_HZ_FULL=y > CONFIG_NO_HZ_FULL_ALL=y > CONFIG_NO_HZ_FULL_SYSIDLE=y > > # default to power-efficient workqueues (which are then set to unbound) > CONFIG_WQ_POWER_EFFICIENT_DEFAULT=y > > # lockup detector sets a 4s timer on every CPU, which wakes CPUs > # from idle. (alternately, can be controlled via procfs, > # e.g: echo 0 > /proc/sys/kernel/watchdog) > #CONFIG_LOCKUP_DETECTOR=n
I had a go with this, but I couldn't seem to trigger any context tracking without forcing CONFIG_CONTEXT_TRACKING_FORCE=y. Does that mean we're missing something else? Anyway, with that forced on, I see the following during boot: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:418 rcu_eqs_enter+0x84/0xa4() Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.15.0-rc8+ #5 Call trace: [<ffffffc000088048>] dump_backtrace+0x0/0x130 [<ffffffc000088188>] show_stack+0x10/0x1c [<ffffffc0004891a0>] dump_stack+0x74/0xbc [<ffffffc0000a45e0>] warn_slowpath_common+0x8c/0xb4 [<ffffffc0000a46cc>] warn_slowpath_null+0x14/0x20 [<ffffffc0000efc14>] rcu_eqs_enter+0x80/0xa4 [<ffffffc0000efc58>] rcu_idle_enter+0x20/0x50 [<ffffffc0000dd314>] cpu_startup_entry+0x118/0x184 [<ffffffc0004865ec>] rest_init+0x7c/0x88 [<ffffffc000609800>] start_kernel+0x368/0x37c ---[ end trace c17313e162496e65 ]--- ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/rcu/tree.c:541 rcu_eqs_exit+0xb0/0xbc() Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 3.15.0-rc8+ #5 Call trace: [<ffffffc000088048>] dump_backtrace+0x0/0x130 [<ffffffc000088188>] show_stack+0x10/0x1c [<ffffffc0004891a0>] dump_stack+0x74/0xbc [<ffffffc0000a45e0>] warn_slowpath_common+0x8c/0xb4 [<ffffffc0000a46cc>] warn_slowpath_null+0x14/0x20 [<ffffffc0000ed384>] rcu_eqs_exit+0xac/0xbc [<ffffffc0000efdac>] rcu_user_exit+0xc/0x18 [<ffffffc00011d48c>] context_tracking_user_exit+0xc4/0xd4 [<ffffffc000083d98>] el1_irq+0x58/0xd4 [<ffffffc0000dd318>] cpu_startup_entry+0x11c/0x184 [<ffffffc0004865ec>] rest_init+0x7c/0x88 [<ffffffc000609800>] start_kernel+0x368/0x37c ---[ end trace c17313e162496e66 ]--- Can you take a look please? I had to fix up some conflicts to apply your patches against our for-next branch, so I've put a branch here for you to look at: git://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git aarch64/context-tracking Cheers, Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
