On Thu, Sep 13, 2012 at 06:52:10PM +0000, Paul Walmsley wrote: > Hi Paul, > > thanks for the reply, > > On Wed, 12 Sep 2012, Paul E. McKenney wrote: > > > Interesting. I am assuming that the interrupt in the stack below came > > from idle, if not, please let me know what. > > According to the exception stack section in the original traceback, it > appears that the serial interrupt took the SoC out of idle. > > > Could you please reproduce with CONFIG_RCU_CPU_STALL_INFO=y? That would > > give me a bit more information about why RCU thought that there was > > a stall. (CCing Becky Bruce, who saw something similar recently.) > > At the bottom of this mail is a series of tracebacks with > CONFIG_RCU_CPU_STALL_INFO=y. Unlike the traceback that was sent in > the last message, these were not triggered by serial activity. These > appeared every 300 seconds. > > > Subodh Nijsure (also CCed) reported something that might be similar on > > ARM, and also reported that setting the following got rid of the stalls: > > > > CONFIG_CPU_IDLE=y > > CONFIG_CPU_IDLE_GOV_LADDER=y > > CONFIG_CPU_IDLE_GOV_MENU=y > > > > At which point he was happy, which was good, but which also left the > > underlying problem unsolved. Do these affect your system? If so, > > do they cause a different ARM idle loop to be executed? > > Will give this a try. What board was Subodh using? Hello, Paul, Any news on trying the above settings? Thanx, Paul > - Paul > > > Debian GNU/Linux wheezy/sid armel ttyO2 > > armel login: [ 305.942108] INFO: rcu_sched self-detected stall on CPU > [ 305.944946] 1: (7 GPs behind) idle=57b/1/0 > [ 305.947265] (t=22811 jiffies) > [ 305.949066] [<c001b7cc>] (unwind_backtrace+0x0/0xf0) from [<c00acc28>] (rcu_check_callbacks+0x1b0/0x678) > [ 305.954223] [<c00acc28>] (rcu_check_callbacks+0x1b0/0x678) from [<c00529e0>] (update_process_times+0x38/0x68) > [ 305.959625] [<c00529e0>] (update_process_times+0x38/0x68) from [<c008bf14>] (tick_sched_timer+0x80/0xec) > [ 305.964813] [<c008bf14>] (tick_sched_timer+0x80/0xec) from [<c006840c>] (__run_hrtimer+0x7c/0x1e0) > [ 305.969696] [<c006840c>] (__run_hrtimer+0x7c/0x1e0) from [<c00691f0>] (hrtimer_interrupt+0x11c/0x2d0) > [ 305.974731] [<c00691f0>] (hrtimer_interrupt+0x11c/0x2d0) from [<c001a04c>] (twd_handler+0x30/0x44) > [ 305.979644] [<c001a04c>] (twd_handler+0x30/0x44) from [<c00a7068>] (handle_percpu_devid_irq+0x90/0x13c) > [ 305.984741] [<c00a7068>] (handle_percpu_devid_irq+0x90/0x13c) from [<c00a37dc>] (generic_handle_irq+0x30/0x48) > [ 305.990234] [<c00a37dc>] (generic_handle_irq+0x30/0x48) from [<c0014c58>] (handle_IRQ+0x4c/0xac) > [ 305.995025] [<c0014c58>] (handle_IRQ+0x4c/0xac) from [<c0008478>] (gic_handle_irq+0x28/0x5c) > [ 305.999633] [<c0008478>] (gic_handle_irq+0x28/0x5c) from [<c04f8ca4>] (__irq_svc+0x44/0x5c) > [ 306.004180] Exception stack(0xde86ff88 to 0xde86ffd0) > [ 306.006927] ff80: 0003c6d0 00000001 00000000 de8660c0 de86e000 c07c23c8 > [ 306.011383] ffa0: c0504590 c0749e20 00000000 411fc092 c074a040 00000000 00000001 de86ffd0 > [ 306.015838] ffc0: 0003c6d1 c0014f50 20000113 ffffffff > [ 306.018585] [<c04f8ca4>] (__irq_svc+0x44/0x5c) from [<c0014f50>] (default_idle+0x20/0x44) > [ 306.023040] [<c0014f50>] (default_idle+0x20/0x44) from [<c001517c>] (cpu_idle+0x9c/0x114) > [ 306.027526] [<c001517c>] (cpu_idle+0x9c/0x114) from [<804f1af4>] (0x804f1af4) > [ 602.004486] INFO: rcu_sched detected stalls on CPUs/tasks: > [ 602.007476] (detected by 0, t=60707 jiffies) > [ 602.009857] INFO: Stall ended before state dump start > [ 906.027893] INFO: rcu_sched self-detected stall on CPU > [ 906.030700] 1: (6 GPs behind) idle=647/1/0 > [ 906.033020] (t=38379 jiffies) > [ 906.034790] [<c001b7cc>] (unwind_backtrace+0x0/0xf0) from [<c00acc28>] (rcu_check_callbacks+0x1b0/0x678) > [ 906.039947] [<c00acc28>] (rcu_check_callbacks+0x1b0/0x678) from [<c00529e0>] (update_process_times+0x38/0x68) > [ 906.045349] [<c00529e0>] (update_process_times+0x38/0x68) from [<c008bf14>] (tick_sched_timer+0x80/0xec) > [ 906.050537] [<c008bf14>] (tick_sched_timer+0x80/0xec) from [<c006840c>] (__run_hrtimer+0x7c/0x1e0) > [ 906.055419] [<c006840c>] (__run_hrtimer+0x7c/0x1e0) from [<c00691f0>] (hrtimer_interrupt+0x11c/0x2d0) > [ 906.060424] [<c00691f0>] (hrtimer_interrupt+0x11c/0x2d0) from [<c001a04c>] (twd_handler+0x30/0x44) > [ 906.065307] [<c001a04c>] (twd_handler+0x30/0x44) from [<c00a7068>] (handle_percpu_devid_irq+0x90/0x13c) > [ 906.070434] [<c00a7068>] (handle_percpu_devid_irq+0x90/0x13c) from [<c00a37dc>] (generic_handle_irq+0x30/0x48) > [ 906.075897] [<c00a37dc>] (generic_handle_irq+0x30/0x48) from [<c0014c58>] (handle_IRQ+0x4c/0xac) > [ 906.080688] [<c0014c58>] (handle_IRQ+0x4c/0xac) from [<c0008478>] (gic_handle_irq+0x28/0x5c) > [ 906.085296] [<c0008478>] (gic_handle_irq+0x28/0x5c) from [<c04f8ca4>] (__irq_svc+0x44/0x5c) > [ 906.089843] Exception stack(0xde86ff88 to 0xde86ffd0) > [ 906.092590] ff80: 0003cb06 00000001 00000000 de8660c0 de86e000 c07c23c8 > [ 906.097045] ffa0: c0504590 c0749e20 00000000 411fc092 c074a040 00000000 00000001 de86ffd0 > [ 906.101501] ffc0: 0003cb07 c0014f50 20000113 ffffffff > [ 906.104278] [<c04f8ca4>] (__irq_svc+0x44/0x5c) from [<c0014f50>] (default_idle+0x20/0x44) > [ 906.108734] [<c0014f50>] (default_idle+0x20/0x44) from [<c001517c>] (cpu_idle+0x9c/0x114) > [ 906.113189] [<c001517c>] (cpu_idle+0x9c/0x114) from [<804f1af4>] (0x804f1af4) > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
