Messages in this thread | | | Date | Mon, 06 Jul 2015 17:27:31 +0100 | From | Sudeep Holla <> | Subject | Re: [patch 1/2] tick/broadcast: Prevent deep idle states if no broadcast device available |
| |
On 06/07/15 17:06, Thomas Gleixner wrote: > On Mon, 6 Jul 2015, Sudeep Holla wrote: >> On 06/07/15 16:35, Thomas Gleixner wrote: >>> Well, we should figure out what happens while we are at it before >>> everything gets paged out again. >>> >> >> True. I just wanted to mention that this patch works for all the >> practical purposes. >> >>> In the case of CONFIG_NOHZ=n and CONFIG_HIGHRES=n the broadcast >>> hrtimer is not compiled as it depends on CONFIG_TICK_ONESHOT, so it >>> works via the bc.evtdev == NULL check. >>> >>> With either option enabled CONFIG_TICK_ONESHOT gets set, so the >>> broadcast timer gets installed but somehow does not work proper if >>> nohz and highres are disabled on the kernel command line. >>> >> >> Let me know if you want to test something to help debug this configuration. > > Can you try the following delta patch? >
I just tried the failing configuration. Yes I am able to boot now, however made below 2 observations:
1. As in the case of CONFIG_HZ_PERIODIC, none of the CPUs enters deeper idle states losing local timers. So the behaviour is same in both versions of periodic mode of timer operation. 2. After boot I am seeing the below warning:
------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at kernel/time/hrtimer.c:1247 __hrtimer_run_queues+0x148/0x150() Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc1 #573 Hardware name: ARM Juno development board (r0) (DT) Call trace: [<ffffffc000089954>] dump_backtrace+0x0/0x124 [<ffffffc000089a88>] show_stack+0x10/0x1c [<ffffffc0005d100c>] dump_stack+0x84/0xc8 [<ffffffc0000b3f34>] warn_slowpath_common+0x98/0xd0 [<ffffffc0000b402c>] warn_slowpath_null+0x14/0x20 [<ffffffc000101eec>] __hrtimer_run_queues+0x144/0x150 [<ffffffc0001028b4>] hrtimer_run_queues+0xb8/0xe8 [<ffffffc000101714>] update_process_times+0x28/0x6c [<ffffffc00010d978>] tick_periodic+0x3c/0xb8 [<ffffffc00010da1c>] tick_handle_periodic+0x28/0x94 [<ffffffc0004d6154>] arch_timer_handler_phys+0x28/0x38 [<ffffffc0000f5964>] handle_percpu_devid_irq+0x74/0x9c [<ffffffc0000f1668>] generic_handle_irq+0x30/0x4c [<ffffffc0000f1984>] __handle_domain_irq+0x5c/0xac [<ffffffc0000824a8>] gic_handle_irq+0x30/0x80 Exception stack(0xffffffc9768ffdb0 to 0xffffffc9768ffed0) fda0: 8c1625f8 00000008 75da4800 ffffffc9 fdc0: 768ffef0 ffffffc9 004b3448 ffffffc0 00000000 00000000 768fc000 ffffffc9 fde0: 00000000 00000000 00000001 00000000 00000002 00000000 00000000 00000000 fe00: da98d76d 001e70a3 000005dc 00000000 00000003 00000000 00000001 00000000 fe20: 00000004 00000000 00000040 00000000 ffffffff ffffffff 00000000 00000000 fe40: 008a3dd8 ffffffc0 ffffffff ffffffff 001a65a0 ffffffc0 004e2488 00000000 fe60: f7ea3080 0000007f 8c1625f8 00000008 75da4800 ffffffc9 00000000 00000000 fe80: 008da840 ffffffc0 8b7dc4e5 00000008 768fff70 ffffffc9 00884e20 ffffffc0 fea0: 005e8770 ffffffc0 00896000 ffffffc0 768fc000 ffffffc9 768ffef0 ffffffc9 fec0: 004b3408 ffffffc0 768ffef0 ffffffc9 [<ffffffc0000855a4>] el1_irq+0x64/0xd8 [<ffffffc0004b354c>] cpuidle_enter+0x14/0x20 [<ffffffc0000e80f8>] call_cpuidle+0x24/0x50 [<ffffffc0000e8268>] cpu_startup_entry+0x144/0x224 [<ffffffc00009010c>] secondary_start_kernel+0x124/0x14c ---[ end trace 87fd96b94f030e33 ]---
| |